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openmpi/ompi/proc/proc.c

575 строки
20 KiB
C
Исходник Обычный вид История

/*
* Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2006 The University of Tennessee and The University
* of Tennessee Research Foundation. All rights
* reserved.
* Copyright (c) 2004-2006 High Performance Computing Center Stuttgart,
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2006 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2006-2007 Cisco Systems, Inc. All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "ompi_config.h"
#include <string.h>
#include "opal/threads/mutex.h"
#include "orte/util/show_help.h"
#include "opal/util/arch.h"
#include "opal/dss/dss.h"
#include "orte/mca/errmgr/errmgr.h"
#include "orte/mca/ess/ess.h"
#include "orte/util/proc_info.h"
#include "orte/util/name_fns.h"
#include "orte/runtime/orte_globals.h"
#include "ompi/proc/proc.h"
#include "ompi/datatype/convertor.h"
#include "ompi/runtime/params.h"
#include "ompi/runtime/mpiruntime.h"
#include "ompi/runtime/ompi_module_exchange.h"
static opal_list_t ompi_proc_list;
static opal_mutex_t ompi_proc_lock;
ompi_proc_t* ompi_proc_local_proc = NULL;
static void ompi_proc_construct(ompi_proc_t* proc);
static void ompi_proc_destruct(ompi_proc_t* proc);
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OBJ_CLASS_INSTANCE(
ompi_proc_t,
opal_list_item_t,
ompi_proc_construct,
2004-10-26 15:39:16 +04:00
ompi_proc_destruct
);
void ompi_proc_construct(ompi_proc_t* proc)
{
proc->proc_bml = NULL;
proc->proc_pml = NULL;
/* By default all processors are supposedly having the same architecture as me. Thus,
* by default we run in a homogeneous environment. Later, when the RTE can tell us
* the arch of the remote nodes, we will have to set the convertors to the correct
* architecture.
*/
proc->proc_arch = orte_process_info.arch;
proc->proc_convertor = ompi_mpi_local_convertor;
OBJ_RETAIN( ompi_mpi_local_convertor );
proc->proc_flags = 0;
/* initialize this pointer to NULL */
proc->proc_hostname = NULL;
}
void ompi_proc_destruct(ompi_proc_t* proc)
{
/* As all the convertors are created with OBJ_NEW we can just call OBJ_RELEASE. All, except
* the local convertor, will get destroyed at some point here. If the reference count is correct
* the local convertor (who has the reference count increased in the datatype) will not get
* destroyed here. It will be destroyed later when the ompi_ddt_finalize is called.
*/
OBJ_RELEASE( proc->proc_convertor );
/* DO NOT FREE THE HOSTNAME FIELD AS THIS POINTS
* TO AN AREA ALLOCATED/FREE'D ELSEWHERE
*/
OPAL_THREAD_LOCK(&ompi_proc_lock);
opal_list_remove_item(&ompi_proc_list, (opal_list_item_t*)proc);
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
}
int ompi_proc_init(void)
{
orte_vpid_t i;
OBJ_CONSTRUCT(&ompi_proc_list, opal_list_t);
OBJ_CONSTRUCT(&ompi_proc_lock, opal_mutex_t);
/* create proc structures and find self */
for( i = 0; i < orte_process_info.num_procs; i++ ) {
ompi_proc_t *proc = OBJ_NEW(ompi_proc_t);
opal_list_append(&ompi_proc_list, (opal_list_item_t*)proc);
proc->proc_name.jobid = ORTE_PROC_MY_NAME->jobid;
proc->proc_name.vpid = i;
if (i == ORTE_PROC_MY_NAME->vpid) {
ompi_proc_local_proc = proc;
proc->proc_flags = OPAL_PROC_ALL_LOCAL;
proc->proc_hostname = orte_process_info.nodename;
proc->proc_arch = orte_process_info.arch;
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
} else {
/* get the locality information */
proc->proc_flags = orte_ess.proc_get_locality(&proc->proc_name);
/* get the name of the node it is on */
proc->proc_hostname = orte_ess.proc_get_hostname(&proc->proc_name);
}
}
return OMPI_SUCCESS;
}
/* in some cases, all MPI procs are required to do a modex so they
* can (at the least) exchange their architecture. Since we cannot
* know in advance if this was required, we provide a separate function
* to set the arch (instead of doing it inside of ompi_proc_init) that
* can be called after the modex completes in ompi_mpi_init. Thus, we
* know that - regardless of how the arch is known, whether via modex
* or dropped in from a local daemon - the arch can be set correctly
* at this time
*/
int ompi_proc_set_arch(void)
{
ompi_proc_t *proc = NULL;
opal_list_item_t *item = NULL;
OPAL_THREAD_LOCK(&ompi_proc_lock);
for( item = opal_list_get_first(&ompi_proc_list);
item != opal_list_get_end(&ompi_proc_list);
item = opal_list_get_next(item)) {
proc = (ompi_proc_t*)item;
if (proc->proc_name.vpid != ORTE_PROC_MY_NAME->vpid) {
proc->proc_arch = orte_ess.proc_get_arch(&proc->proc_name);
/* if arch is different than mine, create a new convertor for this proc */
if (proc->proc_arch != orte_process_info.arch) {
#if OMPI_ENABLE_HETEROGENEOUS_SUPPORT
OBJ_RELEASE(proc->proc_convertor);
proc->proc_convertor = ompi_convertor_create(proc->proc_arch, 0);
#else
This commit represents a bunch of work on a Mercurial side branch. As such, the commit message back to the master SVN repository is fairly long. = ORTE Job-Level Output Messages = Add two new interfaces that should be used for all new code throughout the ORTE and OMPI layers (we already make the search-and-replace on the existing ORTE / OMPI layers): * orte_output(): (and corresponding friends ORTE_OUTPUT, orte_output_verbose, etc.) This function sends the output directly to the HNP for processing as part of a job-specific output channel. It supports all the same outputs as opal_output() (syslog, file, stdout, stderr), but for stdout/stderr, the output is sent to the HNP for processing and output. More on this below. * orte_show_help(): This function is a drop-in-replacement for opal_show_help(), with two differences in functionality: 1. the rendered text help message output is sent to the HNP for display (rather than outputting directly into the process' stderr stream) 1. the HNP detects duplicate help messages and does not display them (so that you don't see the same error message N times, once from each of your N MPI processes); instead, it counts "new" instances of the help message and displays a message every ~5 seconds when there are new ones ("I got X new copies of the help message...") opal_show_help and opal_output still exist, but they only output in the current process. The intent for the new orte_* functions is that they can apply job-level intelligence to the output. As such, we recommend that all new ORTE and OMPI code use the new orte_* functions, not thei opal_* functions. === New code === For ORTE and OMPI programmers, here's what you need to do differently in new code: * Do not include opal/util/show_help.h or opal/util/output.h. Instead, include orte/util/output.h (this one header file has declarations for both the orte_output() series of functions and orte_show_help()). * Effectively s/opal_output/orte_output/gi throughout your code. Note that orte_output_open() takes a slightly different argument list (as a way to pass data to the filtering stream -- see below), so you if explicitly call opal_output_open(), you'll need to slightly adapt to the new signature of orte_output_open(). * Literally s/opal_show_help/orte_show_help/. The function signature is identical. === Notes === * orte_output'ing to stream 0 will do similar to what opal_output'ing did, so leaving a hard-coded "0" as the first argument is safe. * For systems that do not use ORTE's RML or the HNP, the effect of orte_output_* and orte_show_help will be identical to their opal counterparts (the additional information passed to orte_output_open() will be lost!). Indeed, the orte_* functions simply become trivial wrappers to their opal_* counterparts. Note that we have not tested this; the code is simple but it is quite possible that we mucked something up. = Filter Framework = Messages sent view the new orte_* functions described above and messages output via the IOF on the HNP will now optionally be passed through a new "filter" framework before being output to stdout/stderr. The "filter" OPAL MCA framework is intended to allow preprocessing to messages before they are sent to their final destinations. The first component that was written in the filter framework was to create an XML stream, segregating all the messages into different XML tags, etc. This will allow 3rd party tools to read the stdout/stderr from the HNP and be able to know exactly what each text message is (e.g., a help message, another OMPI infrastructure message, stdout from the user process, stderr from the user process, etc.). Filtering is not active by default. Filter components must be specifically requested, such as: {{{ $ mpirun --mca filter xml ... }}} There can only be one filter component active. = New MCA Parameters = The new functionality described above introduces two new MCA parameters: * '''orte_base_help_aggregate''': Defaults to 1 (true), meaning that help messages will be aggregated, as described above. If set to 0, all help messages will be displayed, even if they are duplicates (i.e., the original behavior). * '''orte_base_show_output_recursions''': An MCA parameter to help debug one of the known issues, described below. It is likely that this MCA parameter will disappear before v1.3 final. = Known Issues = * The XML filter component is not complete. The current output from this component is preliminary and not real XML. A bit more work needs to be done to configure.m4 search for an appropriate XML library/link it in/use it at run time. * There are possible recursion loops in the orte_output() and orte_show_help() functions -- e.g., if RML send calls orte_output() or orte_show_help(). We have some ideas how to fix these, but figured that it was ok to commit before feature freeze with known issues. The code currently contains sub-optimal workarounds so that this will not be a problem, but it would be good to actually solve the problem rather than have hackish workarounds before v1.3 final. This commit was SVN r18434.
2008-05-14 00:00:55 +04:00
orte_show_help("help-mpi-runtime",
"heterogeneous-support-unavailable",
true, orte_process_info.nodename,
proc->proc_hostname == NULL ? "<hostname unavailable>" :
proc->proc_hostname);
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return OMPI_ERR_NOT_SUPPORTED;
#endif
}
}
}
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return OMPI_SUCCESS;
}
int ompi_proc_finalize (void)
{
opal_list_item_t *item;
/* remove all items from list and destroy them. Since we cannot know
* the reference count of the procs for certain, it is possible that
* a single OBJ_RELEASE won't drive the count to zero, and hence will
* not release the memory. Accordingly, we cycle through the list here,
* calling release on each item.
*
* This will cycle until it forces the reference count of each item
* to zero, thus causing the destructor to run - which will remove
* the item from the list!
*
* We cannot do this under the thread lock as the destructor will
* call it when removing the item from the list. However, this function
* is ONLY called from MPI_Finalize, and all threads are prohibited from
* calling an MPI function once ANY thread has called MPI_Finalize. Of
* course, multiple threads are allowed to call MPI_Finalize, so this
* function may get called multiple times by various threads. We believe
* it is thread safe to do so...though it may not -appear- to be so
* without walking through the entire list/destructor sequence.
*/
while (opal_list_get_end(&ompi_proc_list) != (item = opal_list_get_first(&ompi_proc_list))) {
OBJ_RELEASE(item);
}
/* now destruct the list and thread lock */
OBJ_DESTRUCT(&ompi_proc_list);
OBJ_DESTRUCT(&ompi_proc_lock);
return OMPI_SUCCESS;
}
ompi_proc_t** ompi_proc_world(size_t *size)
{
ompi_proc_t **procs;
ompi_proc_t *proc;
size_t count = 0;
orte_ns_cmp_bitmask_t mask;
orte_process_name_t my_name;
/* check bozo case */
if (NULL == ompi_proc_local_proc) {
return NULL;
}
mask = ORTE_NS_CMP_JOBID;
my_name = ompi_proc_local_proc->proc_name;
/* First count how many match this jobid */
OPAL_THREAD_LOCK(&ompi_proc_lock);
for (proc = (ompi_proc_t*)opal_list_get_first(&ompi_proc_list);
proc != (ompi_proc_t*)opal_list_get_end(&ompi_proc_list);
proc = (ompi_proc_t*)opal_list_get_next(proc)) {
if (OPAL_EQUAL == orte_util_compare_name_fields(mask, &proc->proc_name, &my_name)) {
++count;
}
}
/* allocate an array */
procs = (ompi_proc_t**) malloc(count * sizeof(ompi_proc_t*));
if (NULL == procs) {
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return NULL;
}
/* now save only the procs that match this jobid */
count = 0;
for (proc = (ompi_proc_t*)opal_list_get_first(&ompi_proc_list);
proc != (ompi_proc_t*)opal_list_get_end(&ompi_proc_list);
proc = (ompi_proc_t*)opal_list_get_next(proc)) {
if (OPAL_EQUAL == orte_util_compare_name_fields(mask, &proc->proc_name, &my_name)) {
/* DO NOT RETAIN THIS OBJECT - the reference count on this
* object will be adjusted by external callers. The intent
* here is to allow the reference count to drop to zero if
* the app no longer desires to communicate with this proc.
* For example, the proc may call comm_disconnect on all
* communicators involving this proc. In such cases, we want
* the proc object to be removed from the list. By not incrementing
* the reference count here, we allow this to occur.
*
* We don't implement that yet, but we are still safe for now as
* the OBJ_NEW in ompi_proc_init owns the initial reference
* count which cannot be released until ompi_proc_finalize is
* called.
*/
procs[count++] = proc;
}
}
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
*size = count;
return procs;
}
ompi_proc_t** ompi_proc_all(size_t* size)
{
ompi_proc_t **procs =
(ompi_proc_t**) malloc(opal_list_get_size(&ompi_proc_list) * sizeof(ompi_proc_t*));
ompi_proc_t *proc;
size_t count = 0;
if (NULL == procs) {
return NULL;
}
OPAL_THREAD_LOCK(&ompi_proc_lock);
for(proc = (ompi_proc_t*)opal_list_get_first(&ompi_proc_list);
proc != (ompi_proc_t*)opal_list_get_end(&ompi_proc_list);
proc = (ompi_proc_t*)opal_list_get_next(proc)) {
/* We know this isn't consistent with the behavior in ompi_proc_world,
* but we are leaving the RETAIN for now because the code using this function
* assumes that the results need to be released when done. It will
* be cleaned up later as the "fix" will impact other places in
* the code
*/
OBJ_RETAIN(proc);
procs[count++] = proc;
}
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
*size = count;
return procs;
}
ompi_proc_t** ompi_proc_self(size_t* size)
{
ompi_proc_t **procs = (ompi_proc_t**) malloc(sizeof(ompi_proc_t*));
if (NULL == procs) {
return NULL;
}
/* We know this isn't consistent with the behavior in ompi_proc_world,
* but we are leaving the RETAIN for now because the code using this function
* assumes that the results need to be released when done. It will
* be cleaned up later as the "fix" will impact other places in
* the code
*/
OBJ_RETAIN(ompi_proc_local_proc);
*procs = ompi_proc_local_proc;
*size = 1;
return procs;
}
ompi_proc_t * ompi_proc_find ( const orte_process_name_t * name )
{
ompi_proc_t *proc, *rproc=NULL;
orte_ns_cmp_bitmask_t mask;
/* return the proc-struct which matches this jobid+process id */
mask = ORTE_NS_CMP_JOBID | ORTE_NS_CMP_VPID;
OPAL_THREAD_LOCK(&ompi_proc_lock);
for(proc = (ompi_proc_t*)opal_list_get_first(&ompi_proc_list);
proc != (ompi_proc_t*)opal_list_get_end(&ompi_proc_list);
proc = (ompi_proc_t*)opal_list_get_next(proc)) {
if (OPAL_EQUAL == orte_util_compare_name_fields(mask, &proc->proc_name, name)) {
rproc = proc;
break;
}
}
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
return rproc;
}
int ompi_proc_refresh(void) {
ompi_proc_t *proc = NULL;
opal_list_item_t *item = NULL;
orte_vpid_t i = 0;
OPAL_THREAD_LOCK(&ompi_proc_lock);
for( item = opal_list_get_first(&ompi_proc_list), i = 0;
item != opal_list_get_end(&ompi_proc_list);
item = opal_list_get_next(item), ++i ) {
proc = (ompi_proc_t*)item;
/* Does not change: proc->proc_name.vpid */
proc->proc_name.jobid = ORTE_PROC_MY_NAME->jobid;
/* Make sure to clear the local flag before we set it below */
proc->proc_flags = 0;
if (i == ORTE_PROC_MY_NAME->vpid) {
ompi_proc_local_proc = proc;
proc->proc_flags = OPAL_PROC_ALL_LOCAL;
proc->proc_hostname = orte_process_info.nodename;
proc->proc_arch = orte_process_info.arch;
} else {
proc->proc_flags = orte_ess.proc_get_locality(&proc->proc_name);
proc->proc_hostname = orte_ess.proc_get_hostname(&proc->proc_name);
proc->proc_arch = orte_ess.proc_get_arch(&proc->proc_name);
/* if arch is different than mine, create a new convertor for this proc */
if (proc->proc_arch != orte_process_info.arch) {
#if OMPI_ENABLE_HETEROGENEOUS_SUPPORT
OBJ_RELEASE(proc->proc_convertor);
proc->proc_convertor = ompi_convertor_create(proc->proc_arch, 0);
#else
This commit represents a bunch of work on a Mercurial side branch. As such, the commit message back to the master SVN repository is fairly long. = ORTE Job-Level Output Messages = Add two new interfaces that should be used for all new code throughout the ORTE and OMPI layers (we already make the search-and-replace on the existing ORTE / OMPI layers): * orte_output(): (and corresponding friends ORTE_OUTPUT, orte_output_verbose, etc.) This function sends the output directly to the HNP for processing as part of a job-specific output channel. It supports all the same outputs as opal_output() (syslog, file, stdout, stderr), but for stdout/stderr, the output is sent to the HNP for processing and output. More on this below. * orte_show_help(): This function is a drop-in-replacement for opal_show_help(), with two differences in functionality: 1. the rendered text help message output is sent to the HNP for display (rather than outputting directly into the process' stderr stream) 1. the HNP detects duplicate help messages and does not display them (so that you don't see the same error message N times, once from each of your N MPI processes); instead, it counts "new" instances of the help message and displays a message every ~5 seconds when there are new ones ("I got X new copies of the help message...") opal_show_help and opal_output still exist, but they only output in the current process. The intent for the new orte_* functions is that they can apply job-level intelligence to the output. As such, we recommend that all new ORTE and OMPI code use the new orte_* functions, not thei opal_* functions. === New code === For ORTE and OMPI programmers, here's what you need to do differently in new code: * Do not include opal/util/show_help.h or opal/util/output.h. Instead, include orte/util/output.h (this one header file has declarations for both the orte_output() series of functions and orte_show_help()). * Effectively s/opal_output/orte_output/gi throughout your code. Note that orte_output_open() takes a slightly different argument list (as a way to pass data to the filtering stream -- see below), so you if explicitly call opal_output_open(), you'll need to slightly adapt to the new signature of orte_output_open(). * Literally s/opal_show_help/orte_show_help/. The function signature is identical. === Notes === * orte_output'ing to stream 0 will do similar to what opal_output'ing did, so leaving a hard-coded "0" as the first argument is safe. * For systems that do not use ORTE's RML or the HNP, the effect of orte_output_* and orte_show_help will be identical to their opal counterparts (the additional information passed to orte_output_open() will be lost!). Indeed, the orte_* functions simply become trivial wrappers to their opal_* counterparts. Note that we have not tested this; the code is simple but it is quite possible that we mucked something up. = Filter Framework = Messages sent view the new orte_* functions described above and messages output via the IOF on the HNP will now optionally be passed through a new "filter" framework before being output to stdout/stderr. The "filter" OPAL MCA framework is intended to allow preprocessing to messages before they are sent to their final destinations. The first component that was written in the filter framework was to create an XML stream, segregating all the messages into different XML tags, etc. This will allow 3rd party tools to read the stdout/stderr from the HNP and be able to know exactly what each text message is (e.g., a help message, another OMPI infrastructure message, stdout from the user process, stderr from the user process, etc.). Filtering is not active by default. Filter components must be specifically requested, such as: {{{ $ mpirun --mca filter xml ... }}} There can only be one filter component active. = New MCA Parameters = The new functionality described above introduces two new MCA parameters: * '''orte_base_help_aggregate''': Defaults to 1 (true), meaning that help messages will be aggregated, as described above. If set to 0, all help messages will be displayed, even if they are duplicates (i.e., the original behavior). * '''orte_base_show_output_recursions''': An MCA parameter to help debug one of the known issues, described below. It is likely that this MCA parameter will disappear before v1.3 final. = Known Issues = * The XML filter component is not complete. The current output from this component is preliminary and not real XML. A bit more work needs to be done to configure.m4 search for an appropriate XML library/link it in/use it at run time. * There are possible recursion loops in the orte_output() and orte_show_help() functions -- e.g., if RML send calls orte_output() or orte_show_help(). We have some ideas how to fix these, but figured that it was ok to commit before feature freeze with known issues. The code currently contains sub-optimal workarounds so that this will not be a problem, but it would be good to actually solve the problem rather than have hackish workarounds before v1.3 final. This commit was SVN r18434.
2008-05-14 00:00:55 +04:00
orte_show_help("help-mpi-runtime",
"heterogeneous-support-unavailable",
true, orte_process_info.nodename,
proc->proc_hostname == NULL ? "<hostname unavailable>" :
proc->proc_hostname);
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return OMPI_ERR_NOT_SUPPORTED;
#endif
}
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
}
}
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return OMPI_SUCCESS;
}
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
int
ompi_proc_pack(ompi_proc_t **proclist, int proclistsize, opal_buffer_t* buf)
{
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
int i, rc;
OPAL_THREAD_LOCK(&ompi_proc_lock);
/* cycle through the provided array, packing the OMPI level
* data for each proc. This data may or may not be included
* in any subsequent modex operation, so we include it here
* to ensure completion of a connect/accept handshake. See
* the ompi/mca/dpm framework for an example of where and how
* this info is used.
*
* Eventually, we will review the procedures that call this
* function to see if duplication of communication can be
* reduced. For now, just go ahead and pack the info so it
* can be sent.
*/
for (i=0; i<proclistsize; i++) {
rc = opal_dss.pack(buf, &(proclist[i]->proc_name), 1, ORTE_NAME);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
if(rc != ORTE_SUCCESS) {
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
ORTE_ERROR_LOG(rc);
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return rc;
}
rc = opal_dss.pack(buf, &(proclist[i]->proc_arch), 1, OPAL_UINT32);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
if(rc != ORTE_SUCCESS) {
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
ORTE_ERROR_LOG(rc);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return rc;
}
rc = opal_dss.pack(buf, &(proclist[i]->proc_hostname), 1, OPAL_STRING);
if(rc != ORTE_SUCCESS) {
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
ORTE_ERROR_LOG(rc);
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return rc;
}
}
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return OMPI_SUCCESS;
}
static ompi_proc_t *
ompi_proc_find_and_add(const orte_process_name_t * name, bool* isnew)
{
ompi_proc_t *proc, *rproc = NULL;
orte_ns_cmp_bitmask_t mask;
/* return the proc-struct which matches this jobid+process id */
mask = ORTE_NS_CMP_JOBID | ORTE_NS_CMP_VPID;
OPAL_THREAD_LOCK(&ompi_proc_lock);
for(proc = (ompi_proc_t*)opal_list_get_first(&ompi_proc_list);
proc != (ompi_proc_t*)opal_list_get_end(&ompi_proc_list);
proc = (ompi_proc_t*)opal_list_get_next(proc)) {
if (OPAL_EQUAL == orte_util_compare_name_fields(mask, &proc->proc_name, name)) {
rproc = proc;
*isnew = false;
break;
}
}
/* if we didn't find this proc in the list, create a new
* proc_t and append it to the list
*/
if (NULL == rproc) {
*isnew = true;
rproc = OBJ_NEW(ompi_proc_t);
if (NULL != rproc) {
opal_list_append(&ompi_proc_list, (opal_list_item_t*)rproc);
rproc->proc_name = *name;
}
/* caller had better fill in the rest of the proc, or there's
going to be pain later... */
}
OPAL_THREAD_UNLOCK(&ompi_proc_lock);
return rproc;
}
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
int
ompi_proc_unpack(opal_buffer_t* buf,
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
int proclistsize, ompi_proc_t ***proclist,
int *newproclistsize, ompi_proc_t ***newproclist)
{
int i;
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
size_t newprocs_len = 0;
ompi_proc_t **plist=NULL, **newprocs = NULL;
/* do not free plist *ever*, since it is used in the remote group
structure of a communicator */
plist = (ompi_proc_t **) calloc (proclistsize, sizeof (ompi_proc_t *));
if ( NULL == plist ) {
return OMPI_ERR_OUT_OF_RESOURCE;
}
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
/* free this on the way out */
newprocs = (ompi_proc_t **) calloc (proclistsize, sizeof (ompi_proc_t *));
if (NULL == newprocs) {
free(plist);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
return OMPI_ERR_OUT_OF_RESOURCE;
}
/* cycle through the array of provided procs and unpack
* their info - as packed by ompi_proc_pack
*/
for ( i=0; i<proclistsize; i++ ){
orte_std_cntr_t count=1;
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
orte_process_name_t new_name;
uint32_t new_arch;
char *new_hostname;
bool isnew = false;
int rc;
rc = opal_dss.unpack(buf, &new_name, &count, ORTE_NAME);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
if (rc != ORTE_SUCCESS) {
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
ORTE_ERROR_LOG(rc);
free(plist);
free(newprocs);
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
return rc;
}
rc = opal_dss.unpack(buf, &new_arch, &count, OPAL_UINT32);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
if (rc != ORTE_SUCCESS) {
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
ORTE_ERROR_LOG(rc);
free(plist);
free(newprocs);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
return rc;
}
rc = opal_dss.unpack(buf, &new_hostname, &count, OPAL_STRING);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
if (rc != ORTE_SUCCESS) {
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
ORTE_ERROR_LOG(rc);
free(plist);
free(newprocs);
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
return rc;
}
/* see if this proc is already on our ompi_proc_list */
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
plist[i] = ompi_proc_find_and_add(&new_name, &isnew);
if (isnew) {
/* if not, then it was added, so update the values
* in the proc_t struct with the info that was passed
* to us
*/
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
newprocs[newprocs_len++] = plist[i];
Repair the MPI-2 dynamic operations. This includes: 1. repair of the linear and direct routed modules 2. repair of the ompi/pubsub/orte module to correctly init routes to the ompi-server, and correctly handle failure to correctly parse the provided ompi-server URI 3. modification of orterun to accept both "file" and "FILE" for designating where the ompi-server URI is to be found - purely a convenience feature 4. resolution of a message ordering problem during the connect/accept handshake that allowed the "send-first" proc to attempt to send to the "recv-first" proc before the HNP had actually updated its routes. Let this be a further reminder to all - message ordering is NOT guaranteed in the OOB 5. Repair the ompi/dpm/orte module to correctly init routes during connect/accept. Reminder to all: messages sent to procs in another job family (i.e., started by a different mpirun) are ALWAYS routed through the respective HNPs. As per the comments in orte/routed, this is REQUIRED to maintain connect/accept (where only the root proc on each side is capable of init'ing the routes), allow communication between mpirun's using different routing modules, and to minimize connections on tools such as ompi-server. It is all taken care of "under the covers" by the OOB to ensure that a route back to the sender is maintained, even when the different mpirun's are using different routed modules. 6. corrections in the orte/odls to ensure proper identification of daemons participating in a dynamic launch 7. corrections in build/nidmap to support update of an existing nidmap during dynamic launch 8. corrected implementation of the update_arch function in the ESS, along with consolidation of a number of ESS operations into base functions for easier maintenance. The ability to support info from multiple jobs was added, although we don't currently do so - this will come later to support further fault recovery strategies 9. minor updates to several functions to remove unnecessary and/or no longer used variables and envar's, add some debugging output, etc. 10. addition of a new macro ORTE_PROC_IS_DAEMON that resolves to true if the provided proc is a daemon There is still more cleanup to be done for efficiency, but this at least works. Tested on single-node Mac, multi-node SLURM via odin. Tests included connect/accept, publish/lookup/unpublish, comm_spawn, comm_spawn_multiple, and singleton comm_spawn. Fixes ticket #1256 This commit was SVN r18804.
2008-07-03 21:53:37 +04:00
/* update all the values */
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
plist[i]->proc_arch = new_arch;
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
/* if arch is different than mine, create a new convertor for this proc */
if (plist[i]->proc_arch != ompi_mpi_local_arch) {
#if OMPI_ENABLE_HETEROGENEOUS_SUPPORT
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
OBJ_RELEASE(plist[i]->proc_convertor);
plist[i]->proc_convertor = ompi_convertor_create(plist[i]->proc_arch, 0);
#else
This commit represents a bunch of work on a Mercurial side branch. As such, the commit message back to the master SVN repository is fairly long. = ORTE Job-Level Output Messages = Add two new interfaces that should be used for all new code throughout the ORTE and OMPI layers (we already make the search-and-replace on the existing ORTE / OMPI layers): * orte_output(): (and corresponding friends ORTE_OUTPUT, orte_output_verbose, etc.) This function sends the output directly to the HNP for processing as part of a job-specific output channel. It supports all the same outputs as opal_output() (syslog, file, stdout, stderr), but for stdout/stderr, the output is sent to the HNP for processing and output. More on this below. * orte_show_help(): This function is a drop-in-replacement for opal_show_help(), with two differences in functionality: 1. the rendered text help message output is sent to the HNP for display (rather than outputting directly into the process' stderr stream) 1. the HNP detects duplicate help messages and does not display them (so that you don't see the same error message N times, once from each of your N MPI processes); instead, it counts "new" instances of the help message and displays a message every ~5 seconds when there are new ones ("I got X new copies of the help message...") opal_show_help and opal_output still exist, but they only output in the current process. The intent for the new orte_* functions is that they can apply job-level intelligence to the output. As such, we recommend that all new ORTE and OMPI code use the new orte_* functions, not thei opal_* functions. === New code === For ORTE and OMPI programmers, here's what you need to do differently in new code: * Do not include opal/util/show_help.h or opal/util/output.h. Instead, include orte/util/output.h (this one header file has declarations for both the orte_output() series of functions and orte_show_help()). * Effectively s/opal_output/orte_output/gi throughout your code. Note that orte_output_open() takes a slightly different argument list (as a way to pass data to the filtering stream -- see below), so you if explicitly call opal_output_open(), you'll need to slightly adapt to the new signature of orte_output_open(). * Literally s/opal_show_help/orte_show_help/. The function signature is identical. === Notes === * orte_output'ing to stream 0 will do similar to what opal_output'ing did, so leaving a hard-coded "0" as the first argument is safe. * For systems that do not use ORTE's RML or the HNP, the effect of orte_output_* and orte_show_help will be identical to their opal counterparts (the additional information passed to orte_output_open() will be lost!). Indeed, the orte_* functions simply become trivial wrappers to their opal_* counterparts. Note that we have not tested this; the code is simple but it is quite possible that we mucked something up. = Filter Framework = Messages sent view the new orte_* functions described above and messages output via the IOF on the HNP will now optionally be passed through a new "filter" framework before being output to stdout/stderr. The "filter" OPAL MCA framework is intended to allow preprocessing to messages before they are sent to their final destinations. The first component that was written in the filter framework was to create an XML stream, segregating all the messages into different XML tags, etc. This will allow 3rd party tools to read the stdout/stderr from the HNP and be able to know exactly what each text message is (e.g., a help message, another OMPI infrastructure message, stdout from the user process, stderr from the user process, etc.). Filtering is not active by default. Filter components must be specifically requested, such as: {{{ $ mpirun --mca filter xml ... }}} There can only be one filter component active. = New MCA Parameters = The new functionality described above introduces two new MCA parameters: * '''orte_base_help_aggregate''': Defaults to 1 (true), meaning that help messages will be aggregated, as described above. If set to 0, all help messages will be displayed, even if they are duplicates (i.e., the original behavior). * '''orte_base_show_output_recursions''': An MCA parameter to help debug one of the known issues, described below. It is likely that this MCA parameter will disappear before v1.3 final. = Known Issues = * The XML filter component is not complete. The current output from this component is preliminary and not real XML. A bit more work needs to be done to configure.m4 search for an appropriate XML library/link it in/use it at run time. * There are possible recursion loops in the orte_output() and orte_show_help() functions -- e.g., if RML send calls orte_output() or orte_show_help(). We have some ideas how to fix these, but figured that it was ok to commit before feature freeze with known issues. The code currently contains sub-optimal workarounds so that this will not be a problem, but it would be good to actually solve the problem rather than have hackish workarounds before v1.3 final. This commit was SVN r18434.
2008-05-14 00:00:55 +04:00
orte_show_help("help-mpi-runtime",
"heterogeneous-support-unavailable",
true, orte_process_info.nodename,
new_hostname == NULL ? "<hostname unavailable>" :
new_hostname);
free(plist);
free(newprocs);
return OMPI_ERR_NOT_SUPPORTED;
#endif
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
}
if (0 == strcmp(ompi_proc_local_proc->proc_hostname,new_hostname)) {
plist[i]->proc_flags |= (OPAL_PROC_ON_NODE | OPAL_PROC_ON_CU | OPAL_PROC_ON_CLUSTER);
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
}
Clean up the way procs are added to the global process list after MPI_INIT: * Do not add new procs to the global list during modex callback or when sharing orte names during accept/connect. For modex, we cache the modex info for later, in case that proc ever does get added to the global proc list. For accept/connect orte name exchange between the roots, we only need the orte name, so no need to add a proc structure anyway. The procs will be added to the global process list during the proc exchange later in the wireup process * Rename proc_get_namebuf and proc_get_proclist to proc_pack and proc_unpack and extend them to include all information needed to build that proc struct on a remote node (which includes ORTE name, architecture, and hostname). Change unpack to call pml_add_procs for the entire list of new procs at once, rather than one at a time. * Remove ompi_proc_find_and_add from the public proc interface and make it a private function. This function would add a half-created proc to the global proc list, so making it harder to call is a good thing. This means that there's only two ways to add new procs into the global proc list at this time: During MPI_INIT via the call to ompi_proc_init, where my job is added to the list and via ompi_proc_unpack using a buffer from a packed proc list sent to us by someone else. Currently, this is enough to implement MPI semantics. We can extend the interface more if we like, but that may require HNP communication to get the remote proc information and I wanted to avoid that if at all possible. Refs trac:564 This commit was SVN r12798. The following Trac tickets were found above: Ticket 564 --> https://svn.open-mpi.org/trac/ompi/ticket/564
2006-12-07 22:56:54 +03:00
/* Save the hostname */
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
plist[i]->proc_hostname = new_hostname;
/* eventually, we will update the orte/mca/ess framework's data
* to contain the info for the new proc. For now, we ignore
* this step since the MPI layer already has all the info
* it requires
*/
}
}
These changes were mostly captured in a prior RFC (except for #2 below) and are aimed specifically at improving startup performance and setting up the remaining modifications described in that RFC. The commit has been tested for C/R and Cray operations, and on Odin (SLURM, rsh) and RoadRunner (TM). I tried to update all environments, but obviously could not test them. I know that Windows needs some work, and have highlighted what is know to be needed in the odls process component. This represents a lot of work by Brian, Tim P, Josh, and myself, with much advice from Jeff and others. For posterity, I have appended a copy of the email describing the work that was done: As we have repeatedly noted, the modex operation in MPI_Init is the single greatest consumer of time during startup. To-date, we have executed that operation as an ORTE stage gate that held the process until a startup message containing all required modex (and OOB contact info - see #3 below) info could be sent to it. Each process would send its data to the HNP's registry, which assembled and sent the message when all processes had reported in. In addition, ORTE had taken responsibility for monitoring process status as it progressed through a series of "stage gates". The process reported its status at each gate, and ORTE would then send a "release" message once all procs had reported in. The incoming changes revamp these procedures in three ways: 1. eliminating the ORTE stage gate system and cleanly delineating responsibility between the OMPI and ORTE layers for MPI init/finalize. The modex stage gate (STG1) has been replaced by a collective operation in the modex itself that performs an allgather on the required modex info. The allgather is implemented using the orte_grpcomm framework since the BTL's are not active at that point. At the moment, the grpcomm framework only has a "basic" component analogous to OMPI's "basic" coll framework - I would recommend that the MPI team create additional, more advanced components to improve performance of this step. The other stage gates have been replaced by orte_grpcomm barrier functions. We tried to use MPI barriers instead (since the BTL's are active at that point), but - as we discussed on the telecon - these are not currently true barriers so the job would hang when we fell through while messages were still in process. Note that the grpcomm barrier doesn't actually resolve that problem, but Brian has pointed out that we are unlikely to ever see it violated. Again, you might want to spend a little time on an advanced barrier algorithm as the one in "basic" is very simplistic. Summarizing this change: ORTE no longer tracks process state nor has direct responsibility for synchronizing jobs. This is now done via collective operations within the MPI layer, albeit using ORTE collective communication services. I -strongly- urge the MPI team to implement advanced collective algorithms to improve the performance of this critical procedure. 2. reducing the volume of data exchanged during modex. Data in the modex consisted of the process name, the name of the node where that process is located (expressed as a string), plus a string representation of all contact info. The nodename was required in order for the modex to determine if the process was local or not - in addition, some people like to have it to print pretty error messages when a connection failed. The size of this data has been reduced in three ways: (a) reducing the size of the process name itself. The process name consisted of two 32-bit fields for the jobid and vpid. This is far larger than any current system, or system likely to exist in the near future, can support. Accordingly, the default size of these fields has been reduced to 16-bits, which means you can have 32k procs in each of 32k jobs. Since the daemons must have a vpid, and we require one daemon/node, this also restricts the default configuration to 32k nodes. To support any future "mega-clusters", a configuration option --enable-jumbo-apps has been added. This option increases the jobid and vpid field sizes to 32-bits. Someday, if necessary, someone can add yet another option to increase them to 64-bits, I suppose. (b) replacing the string nodename with an integer nodeid. Since we have one daemon/node, the nodeid corresponds to the local daemon's vpid. This replaces an often lengthy string with only 2 (or at most 4) bytes, a substantial reduction. (c) when the mca param requesting that nodenames be sent to support pretty error messages, a second mca param is now used to request FQDN - otherwise, the domain name is stripped (by default) from the message to save space. If someone wants to combine those into a single param somehow (perhaps with an argument?), they are welcome to do so - I didn't want to alter what people are already using. While these may seem like small savings, they actually amount to a significant impact when aggregated across the entire modex operation. Since every proc must receive the modex data regardless of the collective used to send it, just reducing the size of the process name removes nearly 400MBytes of communication from a 32k proc job (admittedly, much of this comm may occur in parallel). So it does add up pretty quickly. 3. routing RML messages to reduce connections. The default messaging system remains point-to-point - i.e., each proc opens a socket to every proc it communicates with and sends its messages directly. A new option uses the orteds as routers - i.e., each proc only opens a single socket to its local orted. All messages are sent from the proc to the orted, which forwards the message to the orted on the node where the intended recipient proc is located - that orted then forwards the message to its local proc (the recipient). This greatly reduces the connection storm we have encountered during startup. It also has the benefit of removing the sharing of every proc's OOB contact with every other proc. The orted routing tables are populated during launch since every orted gets a map of where every proc is being placed. Each proc, therefore, only needs to know the contact info for its local daemon, which is passed in via the environment when the proc is fork/exec'd by the daemon. This alone removes ~50 bytes/process of communication that was in the current STG1 startup message - so for our 32k proc job, this saves us roughly 32k*50 = 1.6MBytes sent to 32k procs = 51GBytes of messaging. Note that you can use the new routing method by specifying -mca routed tree - if you so desire. This mode will become the default at some point in the future. There are a few minor additional changes in the commit that I'll just note in passing: * propagation of command line mca params to the orteds - fixes ticket #1073. See note there for details. * requiring of "finalize" prior to "exit" for MPI procs - fixes ticket #1144. See note there for details. * cleanup of some stale header files This commit was SVN r16364.
2007-10-05 23:48:23 +04:00
if (NULL != newproclistsize) *newproclistsize = newprocs_len;
if (NULL != newproclist) {
*newproclist = newprocs;
} else if (newprocs != NULL) {
free(newprocs);
}
*proclist = plist;
return OMPI_SUCCESS;
}