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openmpi/orte/runtime/orte_wait.c
Ralph Castain a200e4f865 As per the RFC, bring in the ORTE async progress code and the rewrite of OOB:
*** THIS RFC INCLUDES A MINOR CHANGE TO THE MPI-RTE INTERFACE ***

Note: during the course of this work, it was necessary to completely separate the MPI and RTE progress engines. There were multiple places in the MPI layer where ORTE_WAIT_FOR_COMPLETION was being used. A new OMPI_WAIT_FOR_COMPLETION macro was created (defined in ompi/mca/rte/rte.h) that simply cycles across opal_progress until the provided flag becomes false. Places where the MPI layer blocked waiting for RTE to complete an event have been modified to use this macro.

***************************************************************************************

I am reissuing this RFC because of the time that has passed since its original release. Since its initial release and review, I have debugged it further to ensure it fully supports tests like loop_spawn. It therefore seems ready for merge back to the trunk. Given its prior review, I have set the timeout for one week.

The code is in  https://bitbucket.org/rhc/ompi-oob2


WHAT:    Rewrite of ORTE OOB

WHY:       Support asynchronous progress and a host of other features

WHEN:    Wed, August 21

SYNOPSIS:
The current OOB has served us well, but a number of limitations have been identified over the years. Specifically:

* it is only progressed when called via opal_progress, which can lead to hangs or recursive calls into libevent (which is not supported by that code)

* we've had issues when multiple NICs are available as the code doesn't "shift" messages between transports - thus, all nodes had to be available via the same TCP interface.

* the OOB "unloads" incoming opal_buffer_t objects during the transmission, thus preventing use of OBJ_RETAIN in the code when repeatedly sending the same message to multiple recipients

* there is no failover mechanism across NICs - if the selected NIC (or its attached switch) fails, we are forced to abort

* only one transport (i.e., component) can be "active"


The revised OOB resolves these problems:

* async progress is used for all application processes, with the progress thread blocking in the event library

* each available TCP NIC is supported by its own TCP module. The ability to asynchronously progress each module independently is provided, but not enabled by default (a runtime MCA parameter turns it "on")

* multi-address TCP NICs (e.g., a NIC with both an IPv4 and IPv6 address, or with virtual interfaces) are supported - reachability is determined by comparing the contact info for a peer against all addresses within the range covered by the address/mask pairs for the NIC.

* a message that arrives on one TCP NIC is automatically shifted to whatever NIC that is connected to the next "hop" if that peer cannot be reached by the incoming NIC. If no TCP module will reach the peer, then the OOB attempts to send the message via all other available components - if none can reach the peer, then an "error" is reported back to the RML, which then calls the errmgr for instructions.

* opal_buffer_t now conforms to standard object rules re OBJ_RETAIN as we no longer "unload" the incoming object

* NIC failure is reported to the TCP component, which then tries to resend the message across any other available TCP NIC. If that doesn't work, then the message is given back to the OOB base to try using other components. If all that fails, then the error is reported to the RML, which reports to the errmgr for instructions

* obviously from the above, multiple OOB components (e.g., TCP and UD) can be active in parallel

* the matching code has been moved to the RML (and out of the OOB/TCP component) so it is independent of transport

* routing is done by the individual OOB modules (as opposed to the RML). Thus, both routed and non-routed transports can simultaneously be active

* all blocking send/recv APIs have been removed. Everything operates asynchronously.


KNOWN LIMITATIONS:

* although provision is made for component failover as described above, the code for doing so has not been fully implemented yet. At the moment, if all connections for a given peer fail, the errmgr is notified of a "lost connection", which by default results in termination of the job if it was a lifeline

* the IPv6 code is present and compiles, but is not complete. Since the current IPv6 support in the OOB doesn't work anyway, I don't consider this a blocker

* routing is performed at the individual module level, yet the active routed component is selected on a global basis. We probably should update that to reflect that different transports may need/choose to route in different ways

* obviously, not every error path has been tested nor necessarily covered

* determining abnormal termination is more challenging than in the old code as we now potentially have multiple ways of connecting to a process. Ideally, we would declare "connection failed" when *all* transports can no longer reach the process, but that requires some additional (possibly complex) code. For now, the code replicates the old behavior only somewhat modified - i.e., if a module sees its connection fail, it checks to see if it is a lifeline. If so, it notifies the errmgr that the lifeline is lost - otherwise, it notifies the errmgr that a non-lifeline connection was lost.

* reachability is determined solely on the basis of a shared subnet address/mask - more sophisticated algorithms (e.g., the one used in the tcp btl) are required to handle routing via gateways

* the RML needs to assign sequence numbers to each message on a per-peer basis. The receiving RML will then deliver messages in order, thus preventing out-of-order messaging in the case where messages travel across different transports or a message needs to be redirected/resent due to failure of a NIC

This commit was SVN r29058.
2013-08-22 16:37:40 +00:00

665 lines
16 KiB
C

/*
* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2008 The University of Tennessee and The University
* of Tennessee Research Foundation. All rights
* reserved.
* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2007-2013 Los Alamos National Security, LLC. All rights
* reserved.
* Copyright (c) 2008 Institut National de Recherche en Informatique
* et Automatique. All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "orte_config.h"
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <assert.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_QUEUE_H
#include <sys/queue.h>
#endif
#include <errno.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include <fcntl.h>
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#include "opal/dss/dss_types.h"
#include "opal/class/opal_object.h"
#include "opal/util/output.h"
#include "opal/class/opal_list.h"
#include "opal/mca/event/event.h"
#include "opal/threads/mutex.h"
#include "opal/threads/condition.h"
#include "opal/sys/atomic.h"
#include "orte/constants.h"
#include "orte/mca/errmgr/errmgr.h"
#include "orte/util/name_fns.h"
#include "orte/runtime/orte_globals.h"
#include "orte/runtime/orte_wait.h"
/*********************************************************************
*
* Timer Object Declaration
*
********************************************************************/
static void timer_const(orte_timer_t *tm)
{
tm->ev = opal_event_alloc();
tm->payload = NULL;
}
static void timer_dest(orte_timer_t *tm)
{
opal_event_free(tm->ev);
}
OBJ_CLASS_INSTANCE(orte_timer_t,
opal_object_t,
timer_const,
timer_dest);
/*********************************************************************
*
* Wait Object Declarations
*
********************************************************************/
#ifdef HAVE_WAITPID
static volatile int cb_enabled = true;
static opal_mutex_t mutex;
static opal_list_t pending_pids;
static opal_list_t registered_cb;
/*********************************************************************
*
* Local Class Declarations
*
********************************************************************/
struct blk_waitpid_data_t {
opal_object_t super;
opal_condition_t *cond;
volatile int done;
volatile int status;
volatile int free;
};
typedef struct blk_waitpid_data_t blk_waitpid_data_t;
struct pending_pids_item_t {
opal_list_item_t super;
pid_t pid;
int status;
};
typedef struct pending_pids_item_t pending_pids_item_t;
struct registered_cb_item_t {
opal_list_item_t super;
pid_t pid;
orte_wait_fn_t callback;
void *data;
};
typedef struct registered_cb_item_t registered_cb_item_t;
struct waitpid_callback_data_t {
pid_t pid;
int status;
int options;
pid_t ret;
opal_mutex_t mutex;
opal_condition_t cond;
volatile bool done;
};
typedef struct waitpid_callback_data_t waitpid_callback_data_t;
/*********************************************************************
*
* Local Class Definitions
*
********************************************************************/
static void
blk_waitpid_data_construct(opal_object_t *obj)
{
blk_waitpid_data_t *data = (blk_waitpid_data_t*) obj;
data->cond = OBJ_NEW(opal_condition_t);
data->done = 0;
data->status = 0;
data->free = 0;
}
static void
blk_waitpid_data_destruct(opal_object_t *obj)
{
blk_waitpid_data_t *data = (blk_waitpid_data_t*) obj;
if (NULL != data->cond) OBJ_RELEASE(data->cond);
}
static OBJ_CLASS_INSTANCE(blk_waitpid_data_t, opal_object_t,
blk_waitpid_data_construct,
blk_waitpid_data_destruct);
static OBJ_CLASS_INSTANCE(pending_pids_item_t, opal_list_item_t, NULL, NULL);
static OBJ_CLASS_INSTANCE(registered_cb_item_t, opal_list_item_t, NULL, NULL);
/*********************************************************************
*
* Local Variables
*
********************************************************************/
static opal_event_t handler;
/*********************************************************************
*
* Local Function Prototypes
*
********************************************************************/
static void blk_waitpid_cb(pid_t wpid, int status, void *data);
static pending_pids_item_t* find_pending_pid(pid_t pid, bool create);
static registered_cb_item_t* find_waiting_cb(pid_t pid, bool create);
static void do_waitall(int options);
static void trigger_callback(registered_cb_item_t *cb,
pending_pids_item_t *pending);
static int register_callback(pid_t pid, orte_wait_fn_t callback,
void *data);
static int unregister_callback(pid_t pid);
void orte_wait_signal_callback(int fd, short event, void *arg);
/*********************************************************************
*
* Interface Functions
*
********************************************************************/
void
orte_wait_disable(void)
{
opal_event_del(&handler);
}
void
orte_wait_enable(void)
{
opal_event_add(&handler, NULL);
}
int
orte_wait_init(void)
{
OBJ_CONSTRUCT(&mutex, opal_mutex_t);
OBJ_CONSTRUCT(&pending_pids, opal_list_t);
OBJ_CONSTRUCT(&registered_cb, opal_list_t);
opal_event_set(orte_event_base,
&handler, SIGCHLD, OPAL_EV_SIGNAL|OPAL_EV_PERSIST,
orte_wait_signal_callback,
&handler);
opal_event_set_priority(&handler, ORTE_SYS_PRI);
opal_event_add(&handler, NULL);
return ORTE_SUCCESS;
}
int
orte_wait_finalize(void)
{
opal_list_item_t *item;
OPAL_THREAD_LOCK(&mutex);
opal_event_del(&handler);
/* clear out the lists */
while (NULL != (item = opal_list_remove_first(&pending_pids))) {
OBJ_RELEASE(item);
}
while (NULL != (item = opal_list_remove_first(&registered_cb))) {
OBJ_RELEASE(item);
}
OPAL_THREAD_UNLOCK(&mutex);
OBJ_DESTRUCT(&mutex);
OBJ_DESTRUCT(&pending_pids);
OBJ_DESTRUCT(&registered_cb);
return ORTE_SUCCESS;
}
int
orte_wait_kill(int sig)
{
opal_list_item_t* item;
OPAL_THREAD_LOCK(&mutex);
do_waitall(0);
while (NULL != (item = opal_list_remove_first(&registered_cb))) {
registered_cb_item_t *cb = (registered_cb_item_t*)item;
pending_pids_item_t *pending = find_pending_pid(cb->pid,false);
if(NULL == pending) {
int status;
kill(cb->pid, sig);
waitpid(cb->pid,&status,0);
} else {
OBJ_RELEASE(pending);
}
OBJ_RELEASE(item);
}
OPAL_THREAD_UNLOCK(&mutex);
return ORTE_SUCCESS;
}
pid_t
orte_waitpid(pid_t wpid, int *status, int options)
{
pending_pids_item_t *pending = NULL;
blk_waitpid_data_t *data = NULL;
struct timespec spintime;
pid_t ret;
if ((wpid <= 0) || (0 != (options & WUNTRACED))) {
errno = ORTE_ERR_NOT_IMPLEMENTED;
return (pid_t) -1;
}
OPAL_THREAD_LOCK(&mutex);
do_waitall(options);
pending = find_pending_pid(wpid, false);
if (NULL != pending) {
*status = pending->status;
ret = pending->pid;
opal_list_remove_item(&pending_pids, (opal_list_item_t*) pending);
OBJ_RELEASE(pending);
goto cleanup;
}
if (0 == (options & WNOHANG)) {
/* blocking - create a blk_waitpid_data_t, register the
callback with it, and wait for the trigger. Hold mutex
until after we register so that waitpid isn't called before
the callback is registered. There is a race condition
between starting to sit in the condition_wait and the
callback being triggered, so poll for completion on the
event just in case. */
data = OBJ_NEW(blk_waitpid_data_t);
if (NULL == data) {
ret = -1;
goto cleanup;
}
register_callback(wpid, blk_waitpid_cb, data);
while (0 == data->done) {
spintime.tv_sec = 0;
spintime.tv_nsec = 1 * 1000 * 1000; /* 1 milliseconds */
opal_condition_timedwait(data->cond,
&mutex,
&spintime);
/* if we have pthreads and progress threads and we are the
event thread, opal_condition_timedwait won't progress
anything, so we need to do it. */
if (opal_using_threads()) {
opal_mutex_unlock(&mutex);
opal_event_loop(orte_event_base, OPAL_EVLOOP_NONBLOCK);
opal_mutex_lock(&mutex);
}
do_waitall(0);
}
ret = wpid;
*status = data->status;
/* Unlock the mutex first, so as to not cause any deadlocks.
We aren't going to touch any variables that could cause
problems with thread badness, so it's ok to be here without
the thread locked. Wich is also the reason we go to done
instead of cleanup. */
OPAL_THREAD_UNLOCK(&mutex);
while (0 == data->free) {
/* don't free the condition variable until we are positive
that the broadcast is done being sent. Otherwise,
pthreads gets really unhappy when we pull the rug out
from under it. Yes, it's spinning. No, we won't spin
for long. */
if (!OPAL_ENABLE_MULTI_THREADS) {
opal_event_loop(orte_event_base, OPAL_EVLOOP_NONBLOCK);
}
}
OBJ_RELEASE(data);
/* see note above while loop for why we jump to done */
goto done;
} else {
/* non-blocking - return what waitpid would */
ret = waitpid(wpid, status, options);
}
cleanup:
OPAL_THREAD_UNLOCK(&mutex);
done:
return ret;
}
int
orte_wait_cb(pid_t wpid, orte_wait_fn_t callback, void *data)
{
int ret;
if (wpid <= 0) return ORTE_ERR_NOT_IMPLEMENTED;
if (NULL == callback) return ORTE_ERR_BAD_PARAM;
OPAL_THREAD_LOCK(&mutex);
ret = register_callback(wpid, callback, data);
do_waitall(0);
OPAL_THREAD_UNLOCK(&mutex);
return ret;
}
int
orte_wait_cb_cancel(pid_t wpid)
{
int ret;
if (wpid <= 0) return ORTE_ERR_BAD_PARAM;
OPAL_THREAD_LOCK(&mutex);
do_waitall(0);
ret = unregister_callback(wpid);
OPAL_THREAD_UNLOCK(&mutex);
return ret;
}
/* callback from the event library whenever a SIGCHLD is received */
void
orte_wait_signal_callback(int fd, short event, void *arg)
{
opal_event_t *signal = (opal_event_t*) arg;
if (SIGCHLD != OPAL_EVENT_SIGNAL(signal)) return;
OPAL_THREAD_LOCK(&mutex);
do_waitall(0);
OPAL_THREAD_UNLOCK(&mutex);
}
int
orte_wait_cb_disable()
{
OPAL_THREAD_LOCK(&mutex);
do_waitall(0);
cb_enabled = false;
OPAL_THREAD_UNLOCK(&mutex);
return ORTE_SUCCESS;
}
int
orte_wait_cb_enable()
{
OPAL_THREAD_LOCK(&mutex);
cb_enabled = true;
do_waitall(0);
OPAL_THREAD_UNLOCK(&mutex);
return ORTE_SUCCESS;
}
/*********************************************************************
*
* Local Functions
*
* None of these functions should lock mutex. All but blk_waitpid_cb
* should only be called if the mutex is already locked.
*
********************************************************************/
static void
blk_waitpid_cb(pid_t wpid, int status, void *data)
{
blk_waitpid_data_t *wp_data = (blk_waitpid_data_t*) data;
wp_data->status = status;
wp_data->done = 1;
opal_condition_signal(wp_data->cond);
wp_data->free = 1;
}
/* -1 will return the first available pid */
static pending_pids_item_t *
find_pending_pid(pid_t pid, bool create)
{
opal_list_item_t *item;
pending_pids_item_t *pending;
for (item = opal_list_get_first(&pending_pids) ;
item != opal_list_get_end(&pending_pids) ;
item = opal_list_get_next(item)) {
pending = (pending_pids_item_t*) item;
if (pending->pid == pid || -1 == pid) {
return pending;
}
}
if (create) {
pending = OBJ_NEW(pending_pids_item_t);
if (NULL == pending) return NULL;
pending->pid = pid;
pending->status = 0;
opal_list_append(&pending_pids, (opal_list_item_t*) pending);
return pending;
}
return NULL;
}
/* pid must be positive */
static registered_cb_item_t *
find_waiting_cb(pid_t pid, bool create)
{
opal_list_item_t *item = NULL;
registered_cb_item_t *reg_cb = NULL;
for (item = opal_list_get_first(&registered_cb) ;
item != opal_list_get_end(&registered_cb) ;
item = opal_list_get_next(item)) {
reg_cb = (registered_cb_item_t*) item;
if (reg_cb->pid == pid) {
return reg_cb;
}
}
if (create) {
reg_cb = OBJ_NEW(registered_cb_item_t);
if (NULL == reg_cb) return NULL;
reg_cb->pid = pid;
reg_cb->callback = NULL;
reg_cb->data = NULL;
opal_list_append(&registered_cb, (opal_list_item_t*) reg_cb);
return reg_cb;
}
return NULL;
}
static void
do_waitall(int options)
{
if (!cb_enabled) return;
while (1) {
int status;
pid_t ret = waitpid(-1, &status, WNOHANG);
pending_pids_item_t *pending;
registered_cb_item_t *cb;
if (-1 == ret && EINTR == errno) continue;
if (ret <= 0) break;
cb = find_waiting_cb(ret, false);
if (NULL == cb) {
pending = OBJ_NEW(pending_pids_item_t);
pending->pid = ret;
pending->status = status;
opal_list_append(&pending_pids, &pending->super);
} else {
opal_list_remove_item(&registered_cb, &cb->super);
OPAL_THREAD_UNLOCK(&mutex);
cb->callback(cb->pid, status, cb->data);
OPAL_THREAD_LOCK(&mutex);
OBJ_RELEASE(cb);
}
}
}
static void
trigger_callback(registered_cb_item_t *cb, pending_pids_item_t *pending)
{
assert(cb->pid == pending->pid);
OPAL_THREAD_UNLOCK(&mutex);
cb->callback(cb->pid, pending->status, cb->data);
OPAL_THREAD_LOCK(&mutex);
opal_list_remove_item(&pending_pids, (opal_list_item_t*) pending);
opal_list_remove_item(&registered_cb, (opal_list_item_t*) cb);
}
static int
register_callback(pid_t pid, orte_wait_fn_t callback, void *data)
{
registered_cb_item_t *reg_cb;
pending_pids_item_t *pending;
/* register the callback */
reg_cb = find_waiting_cb(pid, true);
if (NULL == reg_cb) return ORTE_ERROR;
if (NULL != reg_cb->callback) return ORTE_EXISTS;
reg_cb->callback = callback;
reg_cb->data = data;
/* make sure we shouldn't trigger right now */
pending = find_pending_pid(pid, false);
if (NULL != pending) {
trigger_callback(reg_cb, pending);
}
return ORTE_SUCCESS;
}
static int
unregister_callback(pid_t pid)
{
registered_cb_item_t *reg_cb;
/* register the callback */
reg_cb = find_waiting_cb(pid, false);
if (NULL == reg_cb) return ORTE_ERR_BAD_PARAM;
opal_list_remove_item(&registered_cb, (opal_list_item_t*) reg_cb);
return ORTE_SUCCESS;
}
#else /* no waitpid */
int
orte_wait_init(void) {
return ORTE_SUCCESS;
}
int
orte_wait_finalize(void)
{
return ORTE_SUCCESS;
}
pid_t
orte_waitpid(pid_t wpid, int *status, int options)
{
return ORTE_ERR_NOT_SUPPORTED;
}
int
orte_wait_cb(pid_t wpid, orte_wait_fn_t callback, void *data)
{
return ORTE_ERR_NOT_SUPPORTED;
}
int
orte_wait_cb_cancel(pid_t wpid)
{
return ORTE_ERR_NOT_SUPPORTED;
}
int
orte_wait_cb_disable(void)
{
return ORTE_ERR_NOT_SUPPORTED;
}
int
orte_wait_cb_enable(void)
{
return ORTE_ERR_NOT_SUPPORTED;
}
int
orte_wait_kill(int sig)
{
return ORTE_ERR_NOT_SUPPORTED;
}
#endif