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openmpi/ompi/mca/coll/basic/coll_basic_reduce.c
Rainer Keller 9dea63d63a - Last of intrusive commits (promised)... err for now. 
Anyway, this is blocking the move: do not include pml.h
   if not really needed, aka none of the following used:
     mca_pml
     MCA_PML_CALL
     OMPI_ANY_TAG
     OMPI_ANY_SOURCE
     OMPI_PROC_NULL

 - Notable exceptions (deleting in one header->adding):
   - ompi/mca/mtl/psm/
   - ompi/mca/osc/rdma/
   - ompi/mca/btl/openib/btl_openib_endpoint.c depended on
     pml_base_sendreq.h

 - Tested on Linux/x86-64, this time including make check
   (thanks Jeff and Ralph)

This commit was SVN r20725.
2009-03-04 17:06:51 +00:00

614 строки
21 KiB
C
Исходник Ответственный История

/*
* Copyright (c) 2004-2005 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) 2004-2005 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.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "ompi_config.h"
#include "coll_basic.h"
#include <stdio.h>
#include "mpi.h"
#include "ompi/constants.h"
#include "ompi/mca/coll/coll.h"
#include "ompi/mca/coll/base/coll_tags.h"
#include "ompi/mca/pml/pml.h"
#include "ompi/op/op.h"
/*
* reduce_lin_intra
*
* Function: - reduction using O(N) algorithm
* Accepts: - same as MPI_Reduce()
* Returns: - MPI_SUCCESS or error code
*/
int
mca_coll_basic_reduce_lin_intra(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
int root, struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int i, rank, err, size;
ptrdiff_t true_lb, true_extent, lb, extent;
char *free_buffer = NULL;
char *pml_buffer = NULL;
char *inplace_temp = NULL;
char *inbuf;
/* Initialize */
rank = ompi_comm_rank(comm);
size = ompi_comm_size(comm);
/* If not root, send data to the root. */
if (rank != root) {
err = MCA_PML_CALL(send(sbuf, count, dtype, root,
MCA_COLL_BASE_TAG_REDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
return err;
}
/* Root receives and reduces messages. Allocate buffer to receive
* messages. This comment applies to all collectives in this basic
* module where we allocate a temporary buffer. For the next few
* lines of code, it's tremendously complicated how we decided that
* this was the Right Thing to do. Sit back and enjoy. And prepare
* to have your mind warped. :-)
*
* Recall some definitions (I always get these backwards, so I'm
* going to put them here):
*
* extent: the length from the lower bound to the upper bound -- may
* be considerably larger than the buffer required to hold the data
* (or smaller! But it's easiest to think about when it's larger).
*
* true extent: the exact number of bytes required to hold the data
* in the layout pattern in the datatype.
*
* For example, consider the following buffer (just talking about
* LB, extent, and true extent -- extrapolate for UB; i.e., assume
* the UB equals exactly where the data ends):
*
* A B C
* --------------------------------------------------------
* | | |
* --------------------------------------------------------
*
* There are multiple cases:
*
* 1. A is what we give to MPI_Send (and friends), and A is where
* the data starts, and C is where the data ends. In this case:
*
* - extent: C-A
* - true extent: C-A
* - LB: 0
*
* A C
* --------------------------------------------------------
* | |
* --------------------------------------------------------
* <=======================extent=========================>
* <======================true extent=====================>
*
* 2. A is what we give to MPI_Send (and friends), B is where the
* data starts, and C is where the data ends. In this case:
*
* - extent: C-A
* - true extent: C-B
* - LB: positive
*
* A B C
* --------------------------------------------------------
* | | User buffer |
* --------------------------------------------------------
* <=======================extent=========================>
* <===============true extent=============>
*
* 3. B is what we give to MPI_Send (and friends), A is where the
* data starts, and C is where the data ends. In this case:
*
* - extent: C-A
* - true extent: C-A
* - LB: negative
*
* A B C
* --------------------------------------------------------
* | | User buffer |
* --------------------------------------------------------
* <=======================extent=========================>
* <======================true extent=====================>
*
* 4. MPI_BOTTOM is what we give to MPI_Send (and friends), B is
* where the data starts, and C is where the data ends. In this
* case:
*
* - extent: C-MPI_BOTTOM
* - true extent: C-B
* - LB: [potentially very large] positive
*
* MPI_BOTTOM B C
* --------------------------------------------------------
* | | User buffer |
* --------------------------------------------------------
* <=======================extent=========================>
* <===============true extent=============>
*
* So in all cases, for a temporary buffer, all we need to malloc()
* is a buffer of size true_extent. We therefore need to know two
* pointer values: what value to give to MPI_Send (and friends) and
* what value to give to free(), because they might not be the same.
*
* Clearly, what we give to free() is exactly what was returned from
* malloc(). That part is easy. :-)
*
* What we give to MPI_Send (and friends) is a bit more complicated.
* Let's take the 4 cases from above:
*
* 1. If A is what we give to MPI_Send and A is where the data
* starts, then clearly we give to MPI_Send what we got back from
* malloc().
*
* 2. If B is what we get back from malloc, but we give A to
* MPI_Send, then the buffer range [A,B) represents "dead space"
* -- no data will be put there. So it's safe to give B-LB to
* MPI_Send. More specifically, the LB is positive, so B-LB is
* actually A.
*
* 3. If A is what we get back from malloc, and B is what we give to
* MPI_Send, then the LB is negative, so A-LB will actually equal
* B.
*
* 4. Although this seems like the weirdest case, it's actually
* quite similar to case #2 -- the pointer we give to MPI_Send is
* smaller than the pointer we got back from malloc().
*
* Hence, in all cases, we give (return_from_malloc - LB) to MPI_Send.
*
* This works fine and dandy if we only have (count==1), which we
* rarely do. ;-) So we really need to allocate (true_extent +
* ((count - 1) * extent)) to get enough space for the rest. This may
* be more than is necessary, but it's ok.
*
* Simple, no? :-)
*
*/
ompi_ddt_get_extent(dtype, &lb, &extent);
ompi_ddt_get_true_extent(dtype, &true_lb, &true_extent);
if (MPI_IN_PLACE == sbuf) {
sbuf = rbuf;
inplace_temp = (char*)malloc(true_extent + (count - 1) * extent);
if (NULL == inplace_temp) {
return OMPI_ERR_OUT_OF_RESOURCE;
}
rbuf = inplace_temp - lb;
}
if (size > 1) {
free_buffer = (char*)malloc(true_extent + (count - 1) * extent);
if (NULL == free_buffer) {
return OMPI_ERR_OUT_OF_RESOURCE;
}
pml_buffer = free_buffer - lb;
}
/* Initialize the receive buffer. */
if (rank == (size - 1)) {
err = ompi_ddt_copy_content_same_ddt(dtype, count, (char*)rbuf, (char*)sbuf);
} else {
err = MCA_PML_CALL(recv(rbuf, count, dtype, size - 1,
MCA_COLL_BASE_TAG_REDUCE, comm,
MPI_STATUS_IGNORE));
}
if (MPI_SUCCESS != err) {
if (NULL != free_buffer) {
free(free_buffer);
}
return err;
}
/* Loop receiving and calling reduction function (C or Fortran). */
for (i = size - 2; i >= 0; --i) {
if (rank == i) {
inbuf = (char*)sbuf;
} else {
err = MCA_PML_CALL(recv(pml_buffer, count, dtype, i,
MCA_COLL_BASE_TAG_REDUCE, comm,
MPI_STATUS_IGNORE));
if (MPI_SUCCESS != err) {
if (NULL != free_buffer) {
free(free_buffer);
}
return err;
}
inbuf = pml_buffer;
}
/* Perform the reduction */
ompi_op_reduce(op, inbuf, rbuf, count, dtype);
}
if (NULL != inplace_temp) {
err = ompi_ddt_copy_content_same_ddt(dtype, count, (char*)sbuf, inplace_temp);
free(inplace_temp);
}
if (NULL != free_buffer) {
free(free_buffer);
}
/* All done */
return MPI_SUCCESS;
}
/*
* reduce_log_intra
*
* Function: - reduction using O(log N) algorithm
* Accepts: - same as MPI_Reduce()
* Returns: - MPI_SUCCESS or error code
*
*
* Performing reduction on each dimension of the hypercube.
* An example for 8 procs (dimensions = 3):
*
* Stage 1, reduce on X dimension, 1 -> 0, 3 -> 2, 5 -> 4, 7 -> 6
*
* 6----<---7 proc_0: 0+1
* /| /| proc_1: 1
* / | / | proc_2: 2+3
* / | / | proc_3: 3
* 4----<---5 | proc_4: 4+5
* | 2--< |---3 proc_5: 5
* | / | / proc_6: 6+7
* | / | / proc_7: 7
* |/ |/
* 0----<---1
*
* Stage 2, reduce on Y dimension, 2 -> 0, 6 -> 4
*
* 6--------7 proc_0: 0+1+2+3
* /| /| proc_1: 1
* v | / | proc_2: 2+3
* / | / | proc_3: 3
* 4--------5 | proc_4: 4+5+6+7
* | 2--- |---3 proc_5: 5
* | / | / proc_6: 6+7
* | v | / proc_7: 7
* |/ |/
* 0--------1
*
* Stage 3, reduce on Z dimension, 4 -> 0
*
* 6--------7 proc_0: 0+1+2+3+4+5+6+7
* /| /| proc_1: 1
* / | / | proc_2: 2+3
* / | / | proc_3: 3
* 4--------5 | proc_4: 4+5+6+7
* | 2--- |---3 proc_5: 5
* v / | / proc_6: 6+7
* | / | / proc_7: 7
* |/ |/
* 0--------1
*
*
*/
int
mca_coll_basic_reduce_log_intra(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
int root, struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int i, size, rank, vrank;
int err, peer, dim, mask;
ptrdiff_t true_lb, true_extent, lb, extent;
char *free_buffer = NULL;
char *free_rbuf = NULL;
char *pml_buffer = NULL;
char *snd_buffer = NULL;
char *rcv_buffer = (char*)rbuf;
char *inplace_temp = NULL;
/* JMS Codearound for now -- if the operations is not communative,
* just call the linear algorithm. Need to talk to Edgar / George
* about fixing this algorithm here to work with non-communative
* operations. */
if (!ompi_op_is_commute(op)) {
return mca_coll_basic_reduce_lin_intra(sbuf, rbuf, count, dtype,
op, root, comm, module);
}
/* Some variables */
size = ompi_comm_size(comm);
rank = ompi_comm_rank(comm);
vrank = ompi_op_is_commute(op) ? (rank - root + size) % size : rank;
dim = comm->c_cube_dim;
/* Allocate the incoming and resulting message buffers. See lengthy
* rationale above. */
ompi_ddt_get_extent(dtype, &lb, &extent);
ompi_ddt_get_true_extent(dtype, &true_lb, &true_extent);
free_buffer = (char*)malloc(true_extent + (count - 1) * extent);
if (NULL == free_buffer) {
return OMPI_ERR_OUT_OF_RESOURCE;
}
pml_buffer = free_buffer - lb;
/* read the comment about commutative operations (few lines down
* the page) */
if (ompi_op_is_commute(op)) {
rcv_buffer = pml_buffer;
}
/* Allocate sendbuf in case the MPI_IN_PLACE option has been used. See lengthy
* rationale above. */
if (MPI_IN_PLACE == sbuf) {
inplace_temp = (char*)malloc(true_extent + (count - 1) * extent);
if (NULL == inplace_temp) {
return OMPI_ERR_OUT_OF_RESOURCE;
}
sbuf = inplace_temp - lb;
err = ompi_ddt_copy_content_same_ddt(dtype, count, (char*)sbuf, (char*)rbuf);
}
snd_buffer = (char*)sbuf;
if (rank != root && 0 == (vrank & 1)) {
/* root is the only one required to provide a valid rbuf.
* Assume rbuf is invalid for all other ranks, so fix it up
* here to be valid on all non-leaf ranks */
free_rbuf = (char*)malloc(true_extent + (count - 1) * extent);
if (NULL == free_rbuf) {
free(free_buffer);
return OMPI_ERR_OUT_OF_RESOURCE;
}
rbuf = free_rbuf - lb;
}
/* Loop over cube dimensions. High processes send to low ones in the
* dimension. */
for (i = 0, mask = 1; i < dim; ++i, mask <<= 1) {
/* A high-proc sends to low-proc and stops. */
if (vrank & mask) {
peer = vrank & ~mask;
if (ompi_op_is_commute(op)) {
peer = (peer + root) % size;
}
err = MCA_PML_CALL(send(snd_buffer, count,
dtype, peer, MCA_COLL_BASE_TAG_REDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
if (MPI_SUCCESS != err) {
if (NULL != free_buffer) {
free(free_buffer);
}
if (NULL != free_rbuf) {
free(free_rbuf);
}
return err;
}
snd_buffer = (char*)rbuf;
break;
}
/* A low-proc receives, reduces, and moves to a higher
* dimension. */
else {
peer = vrank | mask;
if (peer >= size) {
continue;
}
if (ompi_op_is_commute(op)) {
peer = (peer + root) % size;
}
/* Most of the time (all except the first one for commutative
* operations) we receive in the user provided buffer
* (rbuf). But the exception is here to allow us to dont have
* to copy from the sbuf to a temporary location. If the
* operation is commutative we dont care in which order we
* apply the operation, so for the first time we can receive
* the data in the pml_buffer and then apply to operation
* between this buffer and the user provided data. */
err = MCA_PML_CALL(recv(rcv_buffer, count, dtype, peer,
MCA_COLL_BASE_TAG_REDUCE, comm,
MPI_STATUS_IGNORE));
if (MPI_SUCCESS != err) {
if (NULL != free_buffer) {
free(free_buffer);
}
if (NULL != free_rbuf) {
free(free_rbuf);
}
return err;
}
/* Perform the operation. The target is always the user
* provided buffer We do the operation only if we receive it
* not in the user buffer */
if (snd_buffer != sbuf) {
/* the target buffer is the locally allocated one */
ompi_op_reduce(op, rcv_buffer, pml_buffer, count, dtype);
} else {
/* If we're commutative, we don't care about the order of
* operations and we can just reduce the operations now.
* If we are not commutative, we have to copy the send
* buffer into a temp buffer (pml_buffer) and then reduce
* what we just received against it. */
if (!ompi_op_is_commute(op)) {
ompi_ddt_copy_content_same_ddt(dtype, count, pml_buffer,
(char*)sbuf);
ompi_op_reduce(op, rbuf, pml_buffer, count, dtype);
} else {
ompi_op_reduce(op, sbuf, pml_buffer, count, dtype);
}
/* now we have to send the buffer containing the computed data */
snd_buffer = pml_buffer;
/* starting from now we always receive in the user
* provided buffer */
rcv_buffer = (char*)rbuf;
}
}
}
/* Get the result to the root if needed. */
err = MPI_SUCCESS;
if (0 == vrank) {
if (root == rank) {
ompi_ddt_copy_content_same_ddt(dtype, count, (char*)rbuf, snd_buffer);
} else {
err = MCA_PML_CALL(send(snd_buffer, count,
dtype, root, MCA_COLL_BASE_TAG_REDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
}
} else if (rank == root) {
err = MCA_PML_CALL(recv(rcv_buffer, count, dtype, 0,
MCA_COLL_BASE_TAG_REDUCE,
comm, MPI_STATUS_IGNORE));
if (rcv_buffer != rbuf) {
ompi_op_reduce(op, rcv_buffer, rbuf, count, dtype);
}
}
if (NULL != inplace_temp) {
free(inplace_temp);
}
if (NULL != free_buffer) {
free(free_buffer);
}
if (NULL != free_rbuf) {
free(free_rbuf);
}
/* All done */
return err;
}
/*
* reduce_lin_inter
*
* Function: - reduction using O(N) algorithm
* Accepts: - same as MPI_Reduce()
* Returns: - MPI_SUCCESS or error code
*/
int
mca_coll_basic_reduce_lin_inter(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
int root, struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int i, err, size;
ptrdiff_t true_lb, true_extent, lb, extent;
char *free_buffer = NULL;
char *pml_buffer = NULL;
/* Initialize */
size = ompi_comm_remote_size(comm);
if (MPI_PROC_NULL == root) {
/* do nothing */
err = OMPI_SUCCESS;
} else if (MPI_ROOT != root) {
/* If not root, send data to the root. */
err = MCA_PML_CALL(send(sbuf, count, dtype, root,
MCA_COLL_BASE_TAG_REDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
} else {
/* Root receives and reduces messages */
ompi_ddt_get_extent(dtype, &lb, &extent);
ompi_ddt_get_true_extent(dtype, &true_lb, &true_extent);
free_buffer = (char*)malloc(true_extent + (count - 1) * extent);
if (NULL == free_buffer) {
return OMPI_ERR_OUT_OF_RESOURCE;
}
pml_buffer = free_buffer - lb;
/* Initialize the receive buffer. */
err = MCA_PML_CALL(recv(rbuf, count, dtype, 0,
MCA_COLL_BASE_TAG_REDUCE, comm,
MPI_STATUS_IGNORE));
if (MPI_SUCCESS != err) {
if (NULL != free_buffer) {
free(free_buffer);
}
return err;
}
/* Loop receiving and calling reduction function (C or Fortran). */
for (i = 1; i < size; i++) {
err = MCA_PML_CALL(recv(pml_buffer, count, dtype, i,
MCA_COLL_BASE_TAG_REDUCE, comm,
MPI_STATUS_IGNORE));
if (MPI_SUCCESS != err) {
if (NULL != free_buffer) {
free(free_buffer);
}
return err;
}
/* Perform the reduction */
ompi_op_reduce(op, pml_buffer, rbuf, count, dtype);
}
if (NULL != free_buffer) {
free(free_buffer);
}
}
/* All done */
return err;
}
/*
* reduce_log_inter
*
* Function: - reduction using O(N) algorithm
* Accepts: - same as MPI_Reduce()
* Returns: - MPI_SUCCESS or error code
*/
int
mca_coll_basic_reduce_log_inter(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
int root, struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
return OMPI_ERR_NOT_IMPLEMENTED;
}
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