1105 строки
47 KiB
C
1105 строки
47 KiB
C
/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
|
|
/*
|
|
* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
|
|
* University Research and Technology
|
|
* Corporation. All rights reserved.
|
|
* Copyright (c) 2004-2017 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) 2013 Los Alamos National Security, LLC. All Rights
|
|
* reserved.
|
|
* Copyright (c) 2015-2016 Research Organization for Information Science
|
|
* and Technology (RIST). All rights reserved.
|
|
* Copyright (c) 2016-2017 IBM Corporation. All rights reserved.
|
|
* Copyright (c) 2018 Siberian State University of Telecommunications
|
|
* and Information Science. All rights reserved.
|
|
* $COPYRIGHT$
|
|
*
|
|
* Additional copyrights may follow
|
|
*
|
|
* $HEADER$
|
|
*/
|
|
|
|
#include "ompi_config.h"
|
|
|
|
#include "mpi.h"
|
|
#include "opal/util/bit_ops.h"
|
|
#include "ompi/constants.h"
|
|
#include "ompi/datatype/ompi_datatype.h"
|
|
#include "ompi/communicator/communicator.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"
|
|
#include "ompi/mca/coll/base/coll_base_functions.h"
|
|
#include "coll_base_topo.h"
|
|
#include "coll_base_util.h"
|
|
|
|
int mca_coll_base_reduce_local(const void *inbuf, void *inoutbuf, int count,
|
|
struct ompi_datatype_t * dtype, struct ompi_op_t * op,
|
|
mca_coll_base_module_t *module)
|
|
{
|
|
/* XXX -- CONST -- do not cast away const -- update ompi/op/op.h */
|
|
ompi_op_reduce(op, (void *)inbuf, inoutbuf, count, dtype);
|
|
return OMPI_SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* This is a generic implementation of the reduce protocol. It used the tree
|
|
* provided as an argument and execute all operations using a segment of
|
|
* count times a datatype.
|
|
* For the last communication it will update the count in order to limit
|
|
* the number of datatype to the original count (original_count)
|
|
*
|
|
* Note that for non-commutative operations we cannot save memory copy
|
|
* for the first block: thus we must copy sendbuf to accumbuf on intermediate
|
|
* to keep the optimized loop happy.
|
|
*/
|
|
int ompi_coll_base_reduce_generic( const void* sendbuf, void* recvbuf, int original_count,
|
|
ompi_datatype_t* datatype, ompi_op_t* op,
|
|
int root, ompi_communicator_t* comm,
|
|
mca_coll_base_module_t *module,
|
|
ompi_coll_tree_t* tree, int count_by_segment,
|
|
int max_outstanding_reqs )
|
|
{
|
|
char *inbuf[2] = {NULL, NULL}, *inbuf_free[2] = {NULL, NULL};
|
|
char *accumbuf = NULL, *accumbuf_free = NULL;
|
|
char *local_op_buffer = NULL, *sendtmpbuf = NULL;
|
|
ptrdiff_t extent, size, gap = 0, segment_increment;
|
|
ompi_request_t **sreq = NULL, *reqs[2] = {MPI_REQUEST_NULL, MPI_REQUEST_NULL};
|
|
int num_segments, line, ret, segindex, i, rank;
|
|
int recvcount, prevcount, inbi;
|
|
|
|
/**
|
|
* Determine number of segments and number of elements
|
|
* sent per operation
|
|
*/
|
|
ompi_datatype_type_extent( datatype, &extent );
|
|
num_segments = (int)(((size_t)original_count + (size_t)count_by_segment - (size_t)1) / (size_t)count_by_segment);
|
|
segment_increment = (ptrdiff_t)count_by_segment * extent;
|
|
|
|
sendtmpbuf = (char*) sendbuf;
|
|
if( sendbuf == MPI_IN_PLACE ) {
|
|
sendtmpbuf = (char *)recvbuf;
|
|
}
|
|
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output, "coll:base:reduce_generic count %d, msg size %ld, segsize %ld, max_requests %d",
|
|
original_count, (unsigned long)((ptrdiff_t)num_segments * (ptrdiff_t)segment_increment),
|
|
(unsigned long)segment_increment, max_outstanding_reqs));
|
|
|
|
rank = ompi_comm_rank(comm);
|
|
|
|
/* non-leaf nodes - wait for children to send me data & forward up
|
|
(if needed) */
|
|
if( tree->tree_nextsize > 0 ) {
|
|
ptrdiff_t real_segment_size;
|
|
|
|
/* handle non existant recv buffer (i.e. its NULL) and
|
|
protect the recv buffer on non-root nodes */
|
|
accumbuf = (char*)recvbuf;
|
|
if( (NULL == accumbuf) || (root != rank) ) {
|
|
/* Allocate temporary accumulator buffer. */
|
|
size = opal_datatype_span(&datatype->super, original_count, &gap);
|
|
accumbuf_free = (char*)malloc(size);
|
|
if (accumbuf_free == NULL) {
|
|
line = __LINE__; ret = -1; goto error_hndl;
|
|
}
|
|
accumbuf = accumbuf_free - gap;
|
|
}
|
|
|
|
/* If this is a non-commutative operation we must copy
|
|
sendbuf to the accumbuf, in order to simplfy the loops */
|
|
|
|
if (!ompi_op_is_commute(op) && MPI_IN_PLACE != sendbuf) {
|
|
ompi_datatype_copy_content_same_ddt(datatype, original_count,
|
|
(char*)accumbuf,
|
|
(char*)sendtmpbuf);
|
|
}
|
|
/* Allocate two buffers for incoming segments */
|
|
real_segment_size = opal_datatype_span(&datatype->super, count_by_segment, &gap);
|
|
inbuf_free[0] = (char*) malloc(real_segment_size);
|
|
if( inbuf_free[0] == NULL ) {
|
|
line = __LINE__; ret = -1; goto error_hndl;
|
|
}
|
|
inbuf[0] = inbuf_free[0] - gap;
|
|
/* if there is chance to overlap communication -
|
|
allocate second buffer */
|
|
if( (num_segments > 1) || (tree->tree_nextsize > 1) ) {
|
|
inbuf_free[1] = (char*) malloc(real_segment_size);
|
|
if( inbuf_free[1] == NULL ) {
|
|
line = __LINE__; ret = -1; goto error_hndl;
|
|
}
|
|
inbuf[1] = inbuf_free[1] - gap;
|
|
}
|
|
|
|
/* reset input buffer index and receive count */
|
|
inbi = 0;
|
|
recvcount = 0;
|
|
/* for each segment */
|
|
for( segindex = 0; segindex <= num_segments; segindex++ ) {
|
|
prevcount = recvcount;
|
|
/* recvcount - number of elements in current segment */
|
|
recvcount = count_by_segment;
|
|
if( segindex == (num_segments-1) )
|
|
recvcount = original_count - (ptrdiff_t)count_by_segment * (ptrdiff_t)segindex;
|
|
|
|
/* for each child */
|
|
for( i = 0; i < tree->tree_nextsize; i++ ) {
|
|
/**
|
|
* We try to overlap communication:
|
|
* either with next segment or with the next child
|
|
*/
|
|
/* post irecv for current segindex on current child */
|
|
if( segindex < num_segments ) {
|
|
void* local_recvbuf = inbuf[inbi];
|
|
if( 0 == i ) {
|
|
/* for the first step (1st child per segment) and
|
|
* commutative operations we might be able to irecv
|
|
* directly into the accumulate buffer so that we can
|
|
* reduce(op) this with our sendbuf in one step as
|
|
* ompi_op_reduce only has two buffer pointers,
|
|
* this avoids an extra memory copy.
|
|
*
|
|
* BUT if the operation is non-commutative or
|
|
* we are root and are USING MPI_IN_PLACE this is wrong!
|
|
*/
|
|
if( (ompi_op_is_commute(op)) &&
|
|
!((MPI_IN_PLACE == sendbuf) && (rank == tree->tree_root)) ) {
|
|
local_recvbuf = accumbuf + (ptrdiff_t)segindex * (ptrdiff_t)segment_increment;
|
|
}
|
|
}
|
|
|
|
ret = MCA_PML_CALL(irecv(local_recvbuf, recvcount, datatype,
|
|
tree->tree_next[i],
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
&reqs[inbi]));
|
|
if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl;}
|
|
}
|
|
/* wait for previous req to complete, if any.
|
|
if there are no requests reqs[inbi ^1] will be
|
|
MPI_REQUEST_NULL. */
|
|
/* wait on data from last child for previous segment */
|
|
ret = ompi_request_wait(&reqs[inbi ^ 1],
|
|
MPI_STATUSES_IGNORE );
|
|
if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
|
|
local_op_buffer = inbuf[inbi ^ 1];
|
|
if( i > 0 ) {
|
|
/* our first operation is to combine our own [sendbuf] data
|
|
* with the data we recvd from down stream (but only
|
|
* the operation is commutative and if we are not root and
|
|
* not using MPI_IN_PLACE)
|
|
*/
|
|
if( 1 == i ) {
|
|
if( (ompi_op_is_commute(op)) &&
|
|
!((MPI_IN_PLACE == sendbuf) && (rank == tree->tree_root)) ) {
|
|
local_op_buffer = sendtmpbuf + (ptrdiff_t)segindex * (ptrdiff_t)segment_increment;
|
|
}
|
|
}
|
|
/* apply operation */
|
|
ompi_op_reduce(op, local_op_buffer,
|
|
accumbuf + (ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
|
|
recvcount, datatype );
|
|
} else if ( segindex > 0 ) {
|
|
void* accumulator = accumbuf + (ptrdiff_t)(segindex-1) * (ptrdiff_t)segment_increment;
|
|
if( tree->tree_nextsize <= 1 ) {
|
|
if( (ompi_op_is_commute(op)) &&
|
|
!((MPI_IN_PLACE == sendbuf) && (rank == tree->tree_root)) ) {
|
|
local_op_buffer = sendtmpbuf + (ptrdiff_t)(segindex-1) * (ptrdiff_t)segment_increment;
|
|
}
|
|
}
|
|
ompi_op_reduce(op, local_op_buffer, accumulator, prevcount,
|
|
datatype );
|
|
|
|
/* all reduced on available data this step (i) complete,
|
|
* pass to the next process unless you are the root.
|
|
*/
|
|
if (rank != tree->tree_root) {
|
|
/* send combined/accumulated data to parent */
|
|
ret = MCA_PML_CALL( send( accumulator, prevcount,
|
|
datatype, tree->tree_prev,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_STANDARD,
|
|
comm) );
|
|
if (ret != MPI_SUCCESS) {
|
|
line = __LINE__; goto error_hndl;
|
|
}
|
|
}
|
|
|
|
/* we stop when segindex = number of segments
|
|
(i.e. we do num_segment+1 steps for pipelining */
|
|
if (segindex == num_segments) break;
|
|
}
|
|
|
|
/* update input buffer index */
|
|
inbi = inbi ^ 1;
|
|
} /* end of for each child */
|
|
} /* end of for each segment */
|
|
|
|
/* clean up */
|
|
if( inbuf_free[0] != NULL) free(inbuf_free[0]);
|
|
if( inbuf_free[1] != NULL) free(inbuf_free[1]);
|
|
if( accumbuf_free != NULL ) free(accumbuf_free);
|
|
}
|
|
|
|
/* leaf nodes
|
|
Depending on the value of max_outstanding_reqs and
|
|
the number of segments we have two options:
|
|
- send all segments using blocking send to the parent, or
|
|
- avoid overflooding the parent nodes by limiting the number of
|
|
outstanding requests to max_oustanding_reqs.
|
|
TODO/POSSIBLE IMPROVEMENT: If there is a way to determine the eager size
|
|
for the current communication, synchronization should be used only
|
|
when the message/segment size is smaller than the eager size.
|
|
*/
|
|
else {
|
|
|
|
/* If the number of segments is less than a maximum number of oustanding
|
|
requests or there is no limit on the maximum number of outstanding
|
|
requests, we send data to the parent using blocking send */
|
|
if ((0 == max_outstanding_reqs) ||
|
|
(num_segments <= max_outstanding_reqs)) {
|
|
|
|
segindex = 0;
|
|
while ( original_count > 0) {
|
|
if (original_count < count_by_segment) {
|
|
count_by_segment = original_count;
|
|
}
|
|
ret = MCA_PML_CALL( send((char*)sendbuf +
|
|
(ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
|
|
count_by_segment, datatype,
|
|
tree->tree_prev,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_STANDARD,
|
|
comm) );
|
|
if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
|
|
segindex++;
|
|
original_count -= count_by_segment;
|
|
}
|
|
}
|
|
|
|
/* Otherwise, introduce flow control:
|
|
- post max_outstanding_reqs non-blocking synchronous send,
|
|
- for remaining segments
|
|
- wait for a ssend to complete, and post the next one.
|
|
- wait for all outstanding sends to complete.
|
|
*/
|
|
else {
|
|
|
|
int creq = 0;
|
|
|
|
sreq = ompi_coll_base_comm_get_reqs(module->base_data, max_outstanding_reqs);
|
|
if (NULL == sreq) { line = __LINE__; ret = -1; goto error_hndl; }
|
|
|
|
/* post first group of requests */
|
|
for (segindex = 0; segindex < max_outstanding_reqs; segindex++) {
|
|
ret = MCA_PML_CALL( isend((char*)sendbuf +
|
|
(ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
|
|
count_by_segment, datatype,
|
|
tree->tree_prev,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_SYNCHRONOUS, comm,
|
|
&sreq[segindex]) );
|
|
if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
|
|
original_count -= count_by_segment;
|
|
}
|
|
|
|
creq = 0;
|
|
while ( original_count > 0 ) {
|
|
/* wait on a posted request to complete */
|
|
ret = ompi_request_wait(&sreq[creq], MPI_STATUS_IGNORE);
|
|
if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
|
|
|
|
if( original_count < count_by_segment ) {
|
|
count_by_segment = original_count;
|
|
}
|
|
ret = MCA_PML_CALL( isend((char*)sendbuf +
|
|
(ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
|
|
count_by_segment, datatype,
|
|
tree->tree_prev,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_SYNCHRONOUS, comm,
|
|
&sreq[creq]) );
|
|
if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
|
|
creq = (creq + 1) % max_outstanding_reqs;
|
|
segindex++;
|
|
original_count -= count_by_segment;
|
|
}
|
|
|
|
/* Wait on the remaining request to complete */
|
|
ret = ompi_request_wait_all( max_outstanding_reqs, sreq,
|
|
MPI_STATUSES_IGNORE );
|
|
if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
|
|
}
|
|
}
|
|
return OMPI_SUCCESS;
|
|
|
|
error_hndl: /* error handler */
|
|
OPAL_OUTPUT (( ompi_coll_base_framework.framework_output,
|
|
"ERROR_HNDL: node %d file %s line %d error %d\n",
|
|
rank, __FILE__, line, ret ));
|
|
(void)line; // silence compiler warning
|
|
if( inbuf_free[0] != NULL ) free(inbuf_free[0]);
|
|
if( inbuf_free[1] != NULL ) free(inbuf_free[1]);
|
|
if( accumbuf_free != NULL ) free(accumbuf);
|
|
if( NULL != sreq ) {
|
|
ompi_coll_base_free_reqs(sreq, max_outstanding_reqs);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Attention: this version of the reduce operations does not
|
|
work for:
|
|
- non-commutative operations
|
|
- segment sizes which are not multiplies of the extent of the datatype
|
|
meaning that at least one datatype must fit in the segment !
|
|
*/
|
|
|
|
int ompi_coll_base_reduce_intra_chain( const void *sendbuf, void *recvbuf, int count,
|
|
ompi_datatype_t* datatype,
|
|
ompi_op_t* op, int root,
|
|
ompi_communicator_t* comm,
|
|
mca_coll_base_module_t *module,
|
|
uint32_t segsize, int fanout,
|
|
int max_outstanding_reqs )
|
|
{
|
|
int segcount = count;
|
|
size_t typelng;
|
|
mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
|
|
mca_coll_base_comm_t *data = base_module->base_data;
|
|
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output,"coll:base:reduce_intra_chain rank %d fo %d ss %5d", ompi_comm_rank(comm), fanout, segsize));
|
|
|
|
COLL_BASE_UPDATE_CHAIN( comm, base_module, root, fanout );
|
|
/**
|
|
* Determine number of segments and number of elements
|
|
* sent per operation
|
|
*/
|
|
ompi_datatype_type_size( datatype, &typelng );
|
|
COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
|
|
|
|
return ompi_coll_base_reduce_generic( sendbuf, recvbuf, count, datatype,
|
|
op, root, comm, module,
|
|
data->cached_chain,
|
|
segcount, max_outstanding_reqs );
|
|
}
|
|
|
|
|
|
int ompi_coll_base_reduce_intra_pipeline( const void *sendbuf, void *recvbuf,
|
|
int count, ompi_datatype_t* datatype,
|
|
ompi_op_t* op, int root,
|
|
ompi_communicator_t* comm,
|
|
mca_coll_base_module_t *module,
|
|
uint32_t segsize,
|
|
int max_outstanding_reqs )
|
|
{
|
|
int segcount = count;
|
|
size_t typelng;
|
|
mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
|
|
mca_coll_base_comm_t *data = base_module->base_data;
|
|
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output,"coll:base:reduce_intra_pipeline rank %d ss %5d",
|
|
ompi_comm_rank(comm), segsize));
|
|
|
|
COLL_BASE_UPDATE_PIPELINE( comm, base_module, root );
|
|
|
|
/**
|
|
* Determine number of segments and number of elements
|
|
* sent per operation
|
|
*/
|
|
ompi_datatype_type_size( datatype, &typelng );
|
|
COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
|
|
|
|
return ompi_coll_base_reduce_generic( sendbuf, recvbuf, count, datatype,
|
|
op, root, comm, module,
|
|
data->cached_pipeline,
|
|
segcount, max_outstanding_reqs );
|
|
}
|
|
|
|
int ompi_coll_base_reduce_intra_binary( const void *sendbuf, void *recvbuf,
|
|
int count, ompi_datatype_t* datatype,
|
|
ompi_op_t* op, int root,
|
|
ompi_communicator_t* comm,
|
|
mca_coll_base_module_t *module,
|
|
uint32_t segsize,
|
|
int max_outstanding_reqs )
|
|
{
|
|
int segcount = count;
|
|
size_t typelng;
|
|
mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
|
|
mca_coll_base_comm_t *data = base_module->base_data;
|
|
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output,"coll:base:reduce_intra_binary rank %d ss %5d",
|
|
ompi_comm_rank(comm), segsize));
|
|
|
|
COLL_BASE_UPDATE_BINTREE( comm, base_module, root );
|
|
|
|
/**
|
|
* Determine number of segments and number of elements
|
|
* sent per operation
|
|
*/
|
|
ompi_datatype_type_size( datatype, &typelng );
|
|
COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
|
|
|
|
return ompi_coll_base_reduce_generic( sendbuf, recvbuf, count, datatype,
|
|
op, root, comm, module,
|
|
data->cached_bintree,
|
|
segcount, max_outstanding_reqs );
|
|
}
|
|
|
|
int ompi_coll_base_reduce_intra_binomial( const void *sendbuf, void *recvbuf,
|
|
int count, ompi_datatype_t* datatype,
|
|
ompi_op_t* op, int root,
|
|
ompi_communicator_t* comm,
|
|
mca_coll_base_module_t *module,
|
|
uint32_t segsize,
|
|
int max_outstanding_reqs )
|
|
{
|
|
int segcount = count;
|
|
size_t typelng;
|
|
mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
|
|
mca_coll_base_comm_t *data = base_module->base_data;
|
|
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output,"coll:base:reduce_intra_binomial rank %d ss %5d",
|
|
ompi_comm_rank(comm), segsize));
|
|
|
|
COLL_BASE_UPDATE_IN_ORDER_BMTREE( comm, base_module, root );
|
|
|
|
/**
|
|
* Determine number of segments and number of elements
|
|
* sent per operation
|
|
*/
|
|
ompi_datatype_type_size( datatype, &typelng );
|
|
COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
|
|
|
|
return ompi_coll_base_reduce_generic( sendbuf, recvbuf, count, datatype,
|
|
op, root, comm, module,
|
|
data->cached_in_order_bmtree,
|
|
segcount, max_outstanding_reqs );
|
|
}
|
|
|
|
/*
|
|
* reduce_intra_in_order_binary
|
|
*
|
|
* Function: Logarithmic reduce operation for non-commutative operations.
|
|
* Acecpts: same as MPI_Reduce()
|
|
* Returns: MPI_SUCCESS or error code
|
|
*/
|
|
int ompi_coll_base_reduce_intra_in_order_binary( const void *sendbuf, void *recvbuf,
|
|
int count,
|
|
ompi_datatype_t* datatype,
|
|
ompi_op_t* op, int root,
|
|
ompi_communicator_t* comm,
|
|
mca_coll_base_module_t *module,
|
|
uint32_t segsize,
|
|
int max_outstanding_reqs )
|
|
{
|
|
int ret, rank, size, io_root, segcount = count;
|
|
void *use_this_sendbuf = NULL;
|
|
void *use_this_recvbuf = NULL;
|
|
char *tmpbuf_free = NULL;
|
|
size_t typelng;
|
|
mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
|
|
mca_coll_base_comm_t *data = base_module->base_data;
|
|
|
|
rank = ompi_comm_rank(comm);
|
|
size = ompi_comm_size(comm);
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output,"coll:base:reduce_intra_in_order_binary rank %d ss %5d",
|
|
rank, segsize));
|
|
|
|
COLL_BASE_UPDATE_IN_ORDER_BINTREE( comm, base_module );
|
|
|
|
/**
|
|
* Determine number of segments and number of elements
|
|
* sent per operation
|
|
*/
|
|
ompi_datatype_type_size( datatype, &typelng );
|
|
COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
|
|
|
|
/* An in-order binary tree must use root (size-1) to preserve the order of
|
|
operations. Thus, if root is not rank (size - 1), then we must handle
|
|
1. MPI_IN_PLACE option on real root, and
|
|
2. we must allocate temporary recvbuf on rank (size - 1).
|
|
Note that generic function must be careful not to switch order of
|
|
operations for non-commutative ops.
|
|
*/
|
|
io_root = size - 1;
|
|
use_this_sendbuf = (void *)sendbuf;
|
|
use_this_recvbuf = recvbuf;
|
|
if (io_root != root) {
|
|
ptrdiff_t dsize, gap = 0;
|
|
char *tmpbuf;
|
|
|
|
dsize = opal_datatype_span(&datatype->super, count, &gap);
|
|
|
|
if ((root == rank) && (MPI_IN_PLACE == sendbuf)) {
|
|
tmpbuf_free = (char *) malloc(dsize);
|
|
if (NULL == tmpbuf_free) {
|
|
return MPI_ERR_INTERN;
|
|
}
|
|
tmpbuf = tmpbuf_free - gap;
|
|
ompi_datatype_copy_content_same_ddt(datatype, count,
|
|
(char*)tmpbuf,
|
|
(char*)recvbuf);
|
|
use_this_sendbuf = tmpbuf;
|
|
} else if (io_root == rank) {
|
|
tmpbuf_free = (char *) malloc(dsize);
|
|
if (NULL == tmpbuf_free) {
|
|
return MPI_ERR_INTERN;
|
|
}
|
|
tmpbuf = tmpbuf_free - gap;
|
|
use_this_recvbuf = tmpbuf;
|
|
}
|
|
}
|
|
|
|
/* Use generic reduce with in-order binary tree topology and io_root */
|
|
ret = ompi_coll_base_reduce_generic( use_this_sendbuf, use_this_recvbuf, count, datatype,
|
|
op, io_root, comm, module,
|
|
data->cached_in_order_bintree,
|
|
segcount, max_outstanding_reqs );
|
|
if (MPI_SUCCESS != ret) { return ret; }
|
|
|
|
/* Clean up */
|
|
if (io_root != root) {
|
|
if (root == rank) {
|
|
/* Receive result from rank io_root to recvbuf */
|
|
ret = MCA_PML_CALL(recv(recvbuf, count, datatype, io_root,
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
MPI_STATUS_IGNORE));
|
|
if (MPI_SUCCESS != ret) { return ret; }
|
|
|
|
} else if (io_root == rank) {
|
|
/* Send result from use_this_recvbuf to root */
|
|
ret = MCA_PML_CALL(send(use_this_recvbuf, count, datatype, root,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_STANDARD, comm));
|
|
if (MPI_SUCCESS != ret) { return ret; }
|
|
}
|
|
}
|
|
if (NULL != tmpbuf_free) {
|
|
free(tmpbuf_free);
|
|
}
|
|
|
|
return MPI_SUCCESS;
|
|
}
|
|
|
|
/*
|
|
* Linear functions are copied from the BASIC coll module
|
|
* they do not segment the message and are simple implementations
|
|
* but for some small number of nodes and/or small data sizes they
|
|
* are just as fast as base/tree based segmenting operations
|
|
* and as such may be selected by the decision functions
|
|
* These are copied into this module due to the way we select modules
|
|
* in V1. i.e. in V2 we will handle this differently and so will not
|
|
* have to duplicate code.
|
|
* GEF Oct05 after asking Jeff.
|
|
*/
|
|
|
|
/*
|
|
* reduce_lin_intra
|
|
*
|
|
* Function: - reduction using O(N) algorithm
|
|
* Accepts: - same as MPI_Reduce()
|
|
* Returns: - MPI_SUCCESS or error code
|
|
*/
|
|
int
|
|
ompi_coll_base_reduce_intra_basic_linear(const 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 extent, dsize, gap = 0;
|
|
char *free_buffer = NULL;
|
|
char *pml_buffer = NULL;
|
|
char *inplace_temp_free = 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;
|
|
}
|
|
|
|
dsize = opal_datatype_span(&dtype->super, count, &gap);
|
|
ompi_datatype_type_extent(dtype, &extent);
|
|
|
|
if (MPI_IN_PLACE == sbuf) {
|
|
sbuf = rbuf;
|
|
inplace_temp_free = (char*)malloc(dsize);
|
|
if (NULL == inplace_temp_free) {
|
|
return OMPI_ERR_OUT_OF_RESOURCE;
|
|
}
|
|
rbuf = inplace_temp_free - gap;
|
|
}
|
|
|
|
if (size > 1) {
|
|
free_buffer = (char*)malloc(dsize);
|
|
if (NULL == free_buffer) {
|
|
if (NULL != inplace_temp_free) {
|
|
free(inplace_temp_free);
|
|
}
|
|
return OMPI_ERR_OUT_OF_RESOURCE;
|
|
}
|
|
pml_buffer = free_buffer - gap;
|
|
}
|
|
|
|
/* Initialize the receive buffer. */
|
|
|
|
if (rank == (size - 1)) {
|
|
err = ompi_datatype_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_free) {
|
|
err = ompi_datatype_copy_content_same_ddt(dtype, count, (char*)sbuf, rbuf);
|
|
free(inplace_temp_free);
|
|
}
|
|
if (NULL != free_buffer) {
|
|
free(free_buffer);
|
|
}
|
|
|
|
/* All done */
|
|
|
|
return MPI_SUCCESS;
|
|
}
|
|
|
|
/*
|
|
* ompi_coll_base_reduce_intra_redscat_gather
|
|
*
|
|
* Function: Reduce using Rabenseifner's algorithm.
|
|
* Accepts: Same arguments as MPI_Reduce
|
|
* Returns: MPI_SUCCESS or error code
|
|
*
|
|
* Description: an implementation of Rabenseifner's reduce algorithm [1, 2].
|
|
* [1] Rajeev Thakur, Rolf Rabenseifner and William Gropp.
|
|
* Optimization of Collective Communication Operations in MPICH //
|
|
* The Int. Journal of High Performance Computing Applications. Vol 19,
|
|
* Issue 1, pp. 49--66.
|
|
* [2] http://www.hlrs.de/mpi/myreduce.html.
|
|
*
|
|
* This algorithm is a combination of a reduce-scatter implemented with
|
|
* recursive vector halving and recursive distance doubling, followed either
|
|
* by a binomial tree gather [1].
|
|
*
|
|
* Step 1. If the number of processes is not a power of two, reduce it to
|
|
* the nearest lower power of two (p' = 2^{\floor{\log_2 p}})
|
|
* by removing r = p - p' extra processes as follows. In the first 2r processes
|
|
* (ranks 0 to 2r - 1), all the even ranks send the second half of the input
|
|
* vector to their right neighbor (rank + 1), and all the odd ranks send
|
|
* the first half of the input vector to their left neighbor (rank - 1).
|
|
* The even ranks compute the reduction on the first half of the vector and
|
|
* the odd ranks compute the reduction on the second half. The odd ranks then
|
|
* send the result to their left neighbors (the even ranks). As a result,
|
|
* the even ranks among the first 2r processes now contain the reduction with
|
|
* the input vector on their right neighbors (the odd ranks). These odd ranks
|
|
* do not participate in the rest of the algorithm, which leaves behind
|
|
* a power-of-two number of processes. The first r even-ranked processes and
|
|
* the last p - 2r processes are now renumbered from 0 to p' - 1.
|
|
*
|
|
* Step 2. The remaining processes now perform a reduce-scatter by using
|
|
* recursive vector halving and recursive distance doubling. The even-ranked
|
|
* processes send the second half of their buffer to rank + 1 and the odd-ranked
|
|
* processes send the first half of their buffer to rank - 1. All processes
|
|
* then compute the reduction between the local buffer and the received buffer.
|
|
* In the next log_2(p') - 1 steps, the buffers are recursively halved, and the
|
|
* distance is doubled. At the end, each of the p' processes has 1 / p' of the
|
|
* total reduction result.
|
|
*
|
|
* Step 3. A binomial tree gather is performed by using recursive vector
|
|
* doubling and distance halving. In the non-power-of-two case, if the root
|
|
* happens to be one of those odd-ranked processes that would normally
|
|
* be removed in the first step, then the role of this process and process 0
|
|
* are interchanged.
|
|
*
|
|
* Limitations:
|
|
* count >= 2^{\floor{\log_2 p}}
|
|
* commutative operations only
|
|
* intra-communicators only
|
|
*
|
|
* Memory requirements (per process):
|
|
* rank != root: 2 * count * typesize + 4 * \log_2(p) * sizeof(int) = O(count)
|
|
* rank == root: count * typesize + 4 * \log_2(p) * sizeof(int) = O(count)
|
|
*
|
|
* Recommendations: root = 0, otherwise it is required additional steps
|
|
* in the root process.
|
|
*/
|
|
int ompi_coll_base_reduce_intra_redscat_gather(
|
|
const 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 comm_size = ompi_comm_size(comm);
|
|
int rank = ompi_comm_rank(comm);
|
|
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
|
|
"coll:base:reduce_intra_redscat_gather: rank %d/%d, root %d",
|
|
rank, comm_size, root));
|
|
|
|
/* Find nearest power-of-two less than or equal to comm_size */
|
|
int nsteps = opal_hibit(comm_size, comm->c_cube_dim + 1); /* ilog2(comm_size) */
|
|
assert(nsteps >= 0);
|
|
int nprocs_pof2 = 1 << nsteps; /* flp2(comm_size) */
|
|
|
|
if (nprocs_pof2 < 2 || count < nprocs_pof2 || !ompi_op_is_commute(op)) {
|
|
OPAL_OUTPUT((ompi_coll_base_framework.framework_output,
|
|
"coll:base:reduce_intra_redscat_gather: rank %d/%d count %d "
|
|
"switching to basic linear reduce", rank, comm_size, count));
|
|
return ompi_coll_base_reduce_intra_basic_linear(sbuf, rbuf, count, dtype,
|
|
op, root, comm, module);
|
|
}
|
|
|
|
int err = MPI_SUCCESS;
|
|
int *rindex = NULL, *rcount = NULL, *sindex = NULL, *scount = NULL;
|
|
ptrdiff_t lb, extent, dsize, gap;
|
|
ompi_datatype_get_extent(dtype, &lb, &extent);
|
|
dsize = opal_datatype_span(&dtype->super, count, &gap);
|
|
|
|
/* Temporary buffers */
|
|
char *tmp_buf_raw = NULL, *rbuf_raw = NULL;
|
|
tmp_buf_raw = malloc(dsize);
|
|
if (NULL == tmp_buf_raw) {
|
|
err = OMPI_ERR_OUT_OF_RESOURCE;
|
|
goto cleanup_and_return;
|
|
}
|
|
char *tmp_buf = tmp_buf_raw - gap;
|
|
|
|
if (rank != root) {
|
|
rbuf_raw = malloc(dsize);
|
|
if (NULL == rbuf_raw) {
|
|
err = OMPI_ERR_OUT_OF_RESOURCE;
|
|
goto cleanup_and_return;
|
|
}
|
|
rbuf = rbuf_raw - gap;
|
|
}
|
|
|
|
if ((rank != root) || (sbuf != MPI_IN_PLACE)) {
|
|
err = ompi_datatype_copy_content_same_ddt(dtype, count, rbuf,
|
|
(char *)sbuf);
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
}
|
|
|
|
/*
|
|
* Step 1. Reduce the number of processes to the nearest lower power of two
|
|
* p' = 2^{\floor{\log_2 p}} by removing r = p - p' processes.
|
|
* 1. In the first 2r processes (ranks 0 to 2r - 1), all the even ranks send
|
|
* the second half of the input vector to their right neighbor (rank + 1)
|
|
* and all the odd ranks send the first half of the input vector to their
|
|
* left neighbor (rank - 1).
|
|
* 2. All 2r processes compute the reduction on their half.
|
|
* 3. The odd ranks then send the result to their left neighbors
|
|
* (the even ranks).
|
|
*
|
|
* The even ranks (0 to 2r - 1) now contain the reduction with the input
|
|
* vector on their right neighbors (the odd ranks). The first r even
|
|
* processes and the p - 2r last processes are renumbered from
|
|
* 0 to 2^{\floor{\log_2 p}} - 1. These odd ranks do not participate in the
|
|
* rest of the algorithm.
|
|
*/
|
|
|
|
int vrank, step, wsize;
|
|
int nprocs_rem = comm_size - nprocs_pof2;
|
|
|
|
if (rank < 2 * nprocs_rem) {
|
|
int count_lhalf = count / 2;
|
|
int count_rhalf = count - count_lhalf;
|
|
|
|
if (rank % 2 != 0) {
|
|
/*
|
|
* Odd process -- exchange with rank - 1
|
|
* Send the left half of the input vector to the left neighbor,
|
|
* Recv the right half of the input vector from the left neighbor
|
|
*/
|
|
err = ompi_coll_base_sendrecv(rbuf, count_lhalf, dtype, rank - 1,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
(char *)tmp_buf + (ptrdiff_t)count_lhalf * extent,
|
|
count_rhalf, dtype, rank - 1,
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
MPI_STATUS_IGNORE, rank);
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
|
|
/* Reduce on the right half of the buffers (result in rbuf) */
|
|
ompi_op_reduce(op, (char *)tmp_buf + (ptrdiff_t)count_lhalf * extent,
|
|
(char *)rbuf + count_lhalf * extent, count_rhalf, dtype);
|
|
|
|
/* Send the right half to the left neighbor */
|
|
err = MCA_PML_CALL(send((char *)rbuf + (ptrdiff_t)count_lhalf * extent,
|
|
count_rhalf, dtype, rank - 1,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_STANDARD, comm));
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
|
|
/* This process does not pariticipate in recursive doubling phase */
|
|
vrank = -1;
|
|
|
|
} else {
|
|
/*
|
|
* Even process -- exchange with rank + 1
|
|
* Send the right half of the input vector to the right neighbor,
|
|
* Recv the left half of the input vector from the right neighbor
|
|
*/
|
|
err = ompi_coll_base_sendrecv((char *)rbuf + (ptrdiff_t)count_lhalf * extent,
|
|
count_rhalf, dtype, rank + 1,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
tmp_buf, count_lhalf, dtype, rank + 1,
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
MPI_STATUS_IGNORE, rank);
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
|
|
/* Reduce on the right half of the buffers (result in rbuf) */
|
|
ompi_op_reduce(op, tmp_buf, rbuf, count_lhalf, dtype);
|
|
|
|
/* Recv the right half from the right neighbor */
|
|
err = MCA_PML_CALL(recv((char *)rbuf + (ptrdiff_t)count_lhalf * extent,
|
|
count_rhalf, dtype, rank + 1,
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
MPI_STATUS_IGNORE));
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
|
|
vrank = rank / 2;
|
|
}
|
|
} else { /* rank >= 2 * nprocs_rem */
|
|
vrank = rank - nprocs_rem;
|
|
}
|
|
|
|
/*
|
|
* Step 2. Reduce-scatter implemented with recursive vector halving and
|
|
* recursive distance doubling. We have p' = 2^{\floor{\log_2 p}}
|
|
* power-of-two number of processes with new ranks (vrank) and result in rbuf.
|
|
*
|
|
* The even-ranked processes send the right half of their buffer to rank + 1
|
|
* and the odd-ranked processes send the left half of their buffer to
|
|
* rank - 1. All processes then compute the reduction between the local
|
|
* buffer and the received buffer. In the next \log_2(p') - 1 steps, the
|
|
* buffers are recursively halved, and the distance is doubled. At the end,
|
|
* each of the p' processes has 1 / p' of the total reduction result.
|
|
*/
|
|
|
|
rindex = malloc(sizeof(*rindex) * nsteps); /* O(\log_2(p)) */
|
|
sindex = malloc(sizeof(*sindex) * nsteps);
|
|
rcount = malloc(sizeof(*rcount) * nsteps);
|
|
scount = malloc(sizeof(*scount) * nsteps);
|
|
if (NULL == rindex || NULL == sindex || NULL == rcount || NULL == scount) {
|
|
err = OMPI_ERR_OUT_OF_RESOURCE;
|
|
goto cleanup_and_return;
|
|
}
|
|
|
|
if (vrank != -1) {
|
|
step = 0;
|
|
wsize = count;
|
|
sindex[0] = rindex[0] = 0;
|
|
|
|
for (int mask = 1; mask < nprocs_pof2; mask <<= 1) {
|
|
/*
|
|
* On each iteration: rindex[step] = sindex[step] -- begining of the
|
|
* current window. Length of the current window is storded in wsize.
|
|
*/
|
|
int vdest = vrank ^ mask;
|
|
/* Translate vdest virtual rank to real rank */
|
|
int dest = (vdest < nprocs_rem) ? vdest * 2 : vdest + nprocs_rem;
|
|
|
|
if (rank < dest) {
|
|
/*
|
|
* Recv into the left half of the current window, send the right
|
|
* half of the window to the peer (perform reduce on the left
|
|
* half of the current window)
|
|
*/
|
|
rcount[step] = wsize / 2;
|
|
scount[step] = wsize - rcount[step];
|
|
sindex[step] = rindex[step] + rcount[step];
|
|
} else {
|
|
/*
|
|
* Recv into the right half of the current window, send the left
|
|
* half of the window to the peer (perform reduce on the right
|
|
* half of the current window)
|
|
*/
|
|
scount[step] = wsize / 2;
|
|
rcount[step] = wsize - scount[step];
|
|
rindex[step] = sindex[step] + scount[step];
|
|
}
|
|
|
|
/* Send part of data from the rbuf, recv into the tmp_buf */
|
|
err = ompi_coll_base_sendrecv((char *)rbuf + (ptrdiff_t)sindex[step] * extent,
|
|
scount[step], dtype, dest,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
(char *)tmp_buf + (ptrdiff_t)rindex[step] * extent,
|
|
rcount[step], dtype, dest,
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
MPI_STATUS_IGNORE, rank);
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
|
|
/* Local reduce: rbuf[] = tmp_buf[] <op> rbuf[] */
|
|
ompi_op_reduce(op, (char *)tmp_buf + (ptrdiff_t)rindex[step] * extent,
|
|
(char *)rbuf + (ptrdiff_t)rindex[step] * extent,
|
|
rcount[step], dtype);
|
|
|
|
/* Move the current window to the received message */
|
|
if (step + 1 < nsteps) {
|
|
rindex[step + 1] = rindex[step];
|
|
sindex[step + 1] = rindex[step];
|
|
wsize = rcount[step];
|
|
step++;
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* Assertion: each process has 1 / p' of the total reduction result:
|
|
* rcount[nsteps - 1] elements in the rbuf[rindex[nsteps - 1], ...].
|
|
*/
|
|
|
|
/*
|
|
* Setup the root process for gather operation.
|
|
* Case 1: root < 2r and root is odd -- root process was excluded on step 1
|
|
* Recv data from process 0, vroot = 0, vrank = 0
|
|
* Case 2: root < 2r and root is even: vroot = root / 2
|
|
* Case 3: root >= 2r: vroot = root - r
|
|
*/
|
|
int vroot = 0;
|
|
if (root < 2 * nprocs_rem) {
|
|
if (root % 2 != 0) {
|
|
vroot = 0;
|
|
if (rank == root) {
|
|
/*
|
|
* Case 1: root < 2r and root is odd -- root process was
|
|
* excluded on step 1 (newrank == -1).
|
|
* Recv a data from the process 0.
|
|
*/
|
|
rindex[0] = 0;
|
|
step = 0, wsize = count;
|
|
for (int mask = 1; mask < nprocs_pof2; mask *= 2) {
|
|
rcount[step] = wsize / 2;
|
|
scount[step] = wsize - rcount[step];
|
|
rindex[step] = 0;
|
|
sindex[step] = rcount[step];
|
|
step++;
|
|
wsize /= 2;
|
|
}
|
|
|
|
err = MCA_PML_CALL(recv(rbuf, rcount[nsteps - 1], dtype, 0,
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
MPI_STATUS_IGNORE));
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
vrank = 0;
|
|
|
|
} else if (vrank == 0) {
|
|
/* Send a data to the root */
|
|
err = MCA_PML_CALL(send(rbuf, rcount[nsteps - 1], dtype, root,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_STANDARD, comm));
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
vrank = -1;
|
|
}
|
|
} else {
|
|
/* Case 2: root < 2r and a root is even: vroot = root / 2 */
|
|
vroot = root / 2;
|
|
}
|
|
} else {
|
|
/* Case 3: root >= 2r: newroot = root - r */
|
|
vroot = root - nprocs_rem;
|
|
}
|
|
|
|
/*
|
|
* Step 3. Gather result at the vroot by the binomial tree algorithm.
|
|
* Each process has 1 / p' of the total reduction result:
|
|
* rcount[nsteps - 1] elements in the rbuf[rindex[nsteps - 1], ...].
|
|
* All exchanges are executed in reverse order relative
|
|
* to recursive doubling (previous step).
|
|
*/
|
|
|
|
if (vrank != -1) {
|
|
int vdest_tree, vroot_tree;
|
|
step = nsteps - 1; /* step = ilog2(p') - 1 */
|
|
|
|
for (int mask = nprocs_pof2 >> 1; mask > 0; mask >>= 1) {
|
|
int vdest = vrank ^ mask;
|
|
/* Translate vdest virtual rank to real rank */
|
|
int dest = (vdest < nprocs_rem) ? vdest * 2 : vdest + nprocs_rem;
|
|
if ((vdest == 0) && (root < 2 * nprocs_rem) && (root % 2 != 0))
|
|
dest = root;
|
|
|
|
vdest_tree = vdest >> step;
|
|
vdest_tree <<= step;
|
|
vroot_tree = vroot >> step;
|
|
vroot_tree <<= step;
|
|
if (vdest_tree == vroot_tree) {
|
|
/* Send data from rbuf and exit */
|
|
err = MCA_PML_CALL(send((char *)rbuf + (ptrdiff_t)rindex[step] * extent,
|
|
rcount[step], dtype, dest,
|
|
MCA_COLL_BASE_TAG_REDUCE,
|
|
MCA_PML_BASE_SEND_STANDARD, comm));
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
break;
|
|
} else {
|
|
/* Recv and continue */
|
|
err = MCA_PML_CALL(recv((char *)rbuf + (ptrdiff_t)sindex[step] * extent,
|
|
scount[step], dtype, dest,
|
|
MCA_COLL_BASE_TAG_REDUCE, comm,
|
|
MPI_STATUS_IGNORE));
|
|
if (MPI_SUCCESS != err) { goto cleanup_and_return; }
|
|
}
|
|
step--;
|
|
}
|
|
}
|
|
|
|
cleanup_and_return:
|
|
if (NULL != tmp_buf_raw)
|
|
free(tmp_buf_raw);
|
|
if (NULL != rbuf_raw)
|
|
free(rbuf_raw);
|
|
if (NULL != rindex)
|
|
free(rindex);
|
|
if (NULL != sindex)
|
|
free(sindex);
|
|
if (NULL != rcount)
|
|
free(rcount);
|
|
if (NULL != scount)
|
|
free(scount);
|
|
return err;
|
|
}
|