a324602174
module_data to hold one with the largest necessary size. This array is only allocated when needed, and it is released upon communicator destruction.
827 строки
35 KiB
C
827 строки
35 KiB
C
/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
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/*
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* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
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* University Research and Technology
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* Corporation. All rights reserved.
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* Copyright (c) 2004-2015 The University of Tennessee and The University
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* of Tennessee Research Foundation. All rights
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* reserved.
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* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
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* University of Stuttgart. All rights reserved.
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* Copyright (c) 2004-2005 The Regents of the University of California.
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* All rights reserved.
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* Copyright (c) 2013 Los Alamos National Security, LLC. All Rights
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* reserved.
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* Copyright (c) 2015 Research Organization for Information Science
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* and Technology (RIST). All rights reserved.
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* $COPYRIGHT$
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*
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* Additional copyrights may follow
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*
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* $HEADER$
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*/
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#include "ompi_config.h"
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#include "mpi.h"
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#include "ompi/constants.h"
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#include "ompi/datatype/ompi_datatype.h"
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#include "ompi/communicator/communicator.h"
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#include "ompi/mca/coll/coll.h"
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#include "ompi/mca/coll/base/coll_tags.h"
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#include "ompi/mca/pml/pml.h"
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#include "ompi/op/op.h"
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#include "ompi/mca/coll/base/coll_base_functions.h"
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#include "coll_base_topo.h"
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/**
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* This is a generic implementation of the reduce protocol. It used the tree
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* provided as an argument and execute all operations using a segment of
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* count times a datatype.
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* For the last communication it will update the count in order to limit
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* the number of datatype to the original count (original_count)
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*
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* Note that for non-commutative operations we cannot save memory copy
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* for the first block: thus we must copy sendbuf to accumbuf on intermediate
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* to keep the optimized loop happy.
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*/
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int ompi_coll_base_reduce_generic( const void* sendbuf, void* recvbuf, int original_count,
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ompi_datatype_t* datatype, ompi_op_t* op,
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int root, ompi_communicator_t* comm,
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mca_coll_base_module_t *module,
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ompi_coll_tree_t* tree, int count_by_segment,
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int max_outstanding_reqs )
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{
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char *inbuf[2] = {NULL, NULL}, *inbuf_free[2] = {NULL, NULL};
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char *accumbuf = NULL, *accumbuf_free = NULL;
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char *local_op_buffer = NULL, *sendtmpbuf = NULL;
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ptrdiff_t extent, lower_bound, segment_increment;
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ompi_request_t **sreq = NULL, *reqs[2] = {MPI_REQUEST_NULL, MPI_REQUEST_NULL};
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int num_segments, line, ret, segindex, i, rank;
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int recvcount, prevcount, inbi;
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size_t typelng;
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/**
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* Determine number of segments and number of elements
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* sent per operation
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*/
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ompi_datatype_get_extent( datatype, &lower_bound, &extent );
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ompi_datatype_type_size( datatype, &typelng );
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num_segments = (original_count + count_by_segment - 1) / count_by_segment;
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segment_increment = (ptrdiff_t)count_by_segment * extent;
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sendtmpbuf = (char*) sendbuf;
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if( sendbuf == MPI_IN_PLACE ) {
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sendtmpbuf = (char *)recvbuf;
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}
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OPAL_OUTPUT((ompi_coll_base_framework.framework_output, "coll:base:reduce_generic count %d, msg size %ld, segsize %ld, max_requests %d",
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original_count, (unsigned long)((ptrdiff_t)num_segments * (ptrdiff_t)segment_increment),
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(unsigned long)segment_increment, max_outstanding_reqs));
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rank = ompi_comm_rank(comm);
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/* non-leaf nodes - wait for children to send me data & forward up
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(if needed) */
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if( tree->tree_nextsize > 0 ) {
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ptrdiff_t true_lower_bound, true_extent, real_segment_size;
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ompi_datatype_get_true_extent( datatype, &true_lower_bound,
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&true_extent );
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/* handle non existant recv buffer (i.e. its NULL) and
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protect the recv buffer on non-root nodes */
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accumbuf = (char*)recvbuf;
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if( (NULL == accumbuf) || (root != rank) ) {
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/* Allocate temporary accumulator buffer. */
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accumbuf_free = (char*)malloc(true_extent +
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(ptrdiff_t)(original_count - 1) * extent);
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if (accumbuf_free == NULL) {
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line = __LINE__; ret = -1; goto error_hndl;
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}
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accumbuf = accumbuf_free - lower_bound;
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}
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/* If this is a non-commutative operation we must copy
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sendbuf to the accumbuf, in order to simplfy the loops */
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if (!ompi_op_is_commute(op)) {
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ompi_datatype_copy_content_same_ddt(datatype, original_count,
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(char*)accumbuf,
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(char*)sendtmpbuf);
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}
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/* Allocate two buffers for incoming segments */
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real_segment_size = true_extent + (ptrdiff_t)(count_by_segment - 1) * extent;
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inbuf_free[0] = (char*) malloc(real_segment_size);
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if( inbuf_free[0] == NULL ) {
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line = __LINE__; ret = -1; goto error_hndl;
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}
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inbuf[0] = inbuf_free[0] - lower_bound;
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/* if there is chance to overlap communication -
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allocate second buffer */
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if( (num_segments > 1) || (tree->tree_nextsize > 1) ) {
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inbuf_free[1] = (char*) malloc(real_segment_size);
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if( inbuf_free[1] == NULL ) {
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line = __LINE__; ret = -1; goto error_hndl;
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}
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inbuf[1] = inbuf_free[1] - lower_bound;
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}
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/* reset input buffer index and receive count */
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inbi = 0;
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recvcount = 0;
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/* for each segment */
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for( segindex = 0; segindex <= num_segments; segindex++ ) {
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prevcount = recvcount;
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/* recvcount - number of elements in current segment */
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recvcount = count_by_segment;
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if( segindex == (num_segments-1) )
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recvcount = original_count - (ptrdiff_t)count_by_segment * (ptrdiff_t)segindex;
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/* for each child */
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for( i = 0; i < tree->tree_nextsize; i++ ) {
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/**
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* We try to overlap communication:
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* either with next segment or with the next child
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*/
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/* post irecv for current segindex on current child */
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if( segindex < num_segments ) {
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void* local_recvbuf = inbuf[inbi];
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if( 0 == i ) {
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/* for the first step (1st child per segment) and
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* commutative operations we might be able to irecv
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* directly into the accumulate buffer so that we can
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* reduce(op) this with our sendbuf in one step as
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* ompi_op_reduce only has two buffer pointers,
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* this avoids an extra memory copy.
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*
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* BUT if the operation is non-commutative or
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* we are root and are USING MPI_IN_PLACE this is wrong!
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*/
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if( (ompi_op_is_commute(op)) &&
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!((MPI_IN_PLACE == sendbuf) && (rank == tree->tree_root)) ) {
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local_recvbuf = accumbuf + (ptrdiff_t)segindex * (ptrdiff_t)segment_increment;
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}
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}
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ret = MCA_PML_CALL(irecv(local_recvbuf, recvcount, datatype,
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tree->tree_next[i],
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MCA_COLL_BASE_TAG_REDUCE, comm,
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&reqs[inbi]));
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if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl;}
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}
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/* wait for previous req to complete, if any.
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if there are no requests reqs[inbi ^1] will be
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MPI_REQUEST_NULL. */
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/* wait on data from last child for previous segment */
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ret = ompi_request_wait_all( 1, &reqs[inbi ^ 1],
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MPI_STATUSES_IGNORE );
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if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
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local_op_buffer = inbuf[inbi ^ 1];
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if( i > 0 ) {
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/* our first operation is to combine our own [sendbuf] data
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* with the data we recvd from down stream (but only
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* the operation is commutative and if we are not root and
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* not using MPI_IN_PLACE)
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*/
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if( 1 == i ) {
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if( (ompi_op_is_commute(op)) &&
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!((MPI_IN_PLACE == sendbuf) && (rank == tree->tree_root)) ) {
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local_op_buffer = sendtmpbuf + (ptrdiff_t)segindex * (ptrdiff_t)segment_increment;
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}
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}
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/* apply operation */
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ompi_op_reduce(op, local_op_buffer,
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accumbuf + (ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
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recvcount, datatype );
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} else if ( segindex > 0 ) {
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void* accumulator = accumbuf + (ptrdiff_t)(segindex-1) * (ptrdiff_t)segment_increment;
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if( tree->tree_nextsize <= 1 ) {
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if( (ompi_op_is_commute(op)) &&
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!((MPI_IN_PLACE == sendbuf) && (rank == tree->tree_root)) ) {
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local_op_buffer = sendtmpbuf + (ptrdiff_t)(segindex-1) * (ptrdiff_t)segment_increment;
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}
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}
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ompi_op_reduce(op, local_op_buffer, accumulator, prevcount,
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datatype );
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/* all reduced on available data this step (i) complete,
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* pass to the next process unless you are the root.
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*/
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if (rank != tree->tree_root) {
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/* send combined/accumulated data to parent */
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ret = MCA_PML_CALL( send( accumulator, prevcount,
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datatype, tree->tree_prev,
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MCA_COLL_BASE_TAG_REDUCE,
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MCA_PML_BASE_SEND_STANDARD,
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comm) );
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if (ret != MPI_SUCCESS) {
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line = __LINE__; goto error_hndl;
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}
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}
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/* we stop when segindex = number of segments
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(i.e. we do num_segment+1 steps for pipelining */
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if (segindex == num_segments) break;
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}
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/* update input buffer index */
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inbi = inbi ^ 1;
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} /* end of for each child */
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} /* end of for each segment */
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/* clean up */
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if( inbuf_free[0] != NULL) free(inbuf_free[0]);
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if( inbuf_free[1] != NULL) free(inbuf_free[1]);
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if( accumbuf_free != NULL ) free(accumbuf_free);
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}
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/* leaf nodes
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Depending on the value of max_outstanding_reqs and
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the number of segments we have two options:
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- send all segments using blocking send to the parent, or
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- avoid overflooding the parent nodes by limiting the number of
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outstanding requests to max_oustanding_reqs.
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TODO/POSSIBLE IMPROVEMENT: If there is a way to determine the eager size
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for the current communication, synchronization should be used only
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when the message/segment size is smaller than the eager size.
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*/
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else {
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/* If the number of segments is less than a maximum number of oustanding
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requests or there is no limit on the maximum number of outstanding
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requests, we send data to the parent using blocking send */
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if ((0 == max_outstanding_reqs) ||
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(num_segments <= max_outstanding_reqs)) {
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segindex = 0;
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while ( original_count > 0) {
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if (original_count < count_by_segment) {
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count_by_segment = original_count;
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}
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ret = MCA_PML_CALL( send((char*)sendbuf +
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(ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
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count_by_segment, datatype,
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tree->tree_prev,
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MCA_COLL_BASE_TAG_REDUCE,
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MCA_PML_BASE_SEND_STANDARD,
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comm) );
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if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
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segindex++;
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original_count -= count_by_segment;
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}
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}
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/* Otherwise, introduce flow control:
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- post max_outstanding_reqs non-blocking synchronous send,
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- for remaining segments
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- wait for a ssend to complete, and post the next one.
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- wait for all outstanding sends to complete.
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*/
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else {
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int creq = 0;
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sreq = coll_base_comm_get_reqs(module->base_data, max_outstanding_reqs);
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if (NULL == sreq) { line = __LINE__; ret = -1; goto error_hndl; }
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/* post first group of requests */
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for (segindex = 0; segindex < max_outstanding_reqs; segindex++) {
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ret = MCA_PML_CALL( isend((char*)sendbuf +
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(ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
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count_by_segment, datatype,
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tree->tree_prev,
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MCA_COLL_BASE_TAG_REDUCE,
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MCA_PML_BASE_SEND_SYNCHRONOUS, comm,
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&sreq[segindex]) );
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if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
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original_count -= count_by_segment;
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}
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creq = 0;
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while ( original_count > 0 ) {
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/* wait on a posted request to complete */
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ret = ompi_request_wait(&sreq[creq], MPI_STATUS_IGNORE);
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if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
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if( original_count < count_by_segment ) {
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count_by_segment = original_count;
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}
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ret = MCA_PML_CALL( isend((char*)sendbuf +
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(ptrdiff_t)segindex * (ptrdiff_t)segment_increment,
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count_by_segment, datatype,
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tree->tree_prev,
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MCA_COLL_BASE_TAG_REDUCE,
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MCA_PML_BASE_SEND_SYNCHRONOUS, comm,
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&sreq[creq]) );
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if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
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creq = (creq + 1) % max_outstanding_reqs;
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segindex++;
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original_count -= count_by_segment;
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}
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/* Wait on the remaining request to complete */
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ret = ompi_request_wait_all( max_outstanding_reqs, sreq,
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MPI_STATUSES_IGNORE );
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if (ret != MPI_SUCCESS) { line = __LINE__; goto error_hndl; }
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}
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}
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return OMPI_SUCCESS;
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error_hndl: /* error handler */
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OPAL_OUTPUT (( ompi_coll_base_framework.framework_output,
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"ERROR_HNDL: node %d file %s line %d error %d\n",
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rank, __FILE__, line, ret ));
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if( inbuf_free[0] != NULL ) free(inbuf_free[0]);
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if( inbuf_free[1] != NULL ) free(inbuf_free[1]);
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if( accumbuf_free != NULL ) free(accumbuf);
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if( NULL != sreq ) {
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ompi_coll_base_free_reqs(sreq, max_outstanding_reqs);
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}
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return ret;
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}
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/* Attention: this version of the reduce operations does not
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work for:
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- non-commutative operations
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- segment sizes which are not multiplies of the extent of the datatype
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meaning that at least one datatype must fit in the segment !
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*/
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int ompi_coll_base_reduce_intra_chain( const void *sendbuf, void *recvbuf, int count,
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ompi_datatype_t* datatype,
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ompi_op_t* op, int root,
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ompi_communicator_t* comm,
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mca_coll_base_module_t *module,
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uint32_t segsize, int fanout,
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int max_outstanding_reqs )
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{
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int segcount = count;
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size_t typelng;
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mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
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mca_coll_base_comm_t *data = base_module->base_data;
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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));
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COLL_BASE_UPDATE_CHAIN( comm, base_module, root, fanout );
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/**
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* Determine number of segments and number of elements
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* sent per operation
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*/
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ompi_datatype_type_size( datatype, &typelng );
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COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
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return ompi_coll_base_reduce_generic( sendbuf, recvbuf, count, datatype,
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op, root, comm, module,
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data->cached_chain,
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segcount, max_outstanding_reqs );
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}
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int ompi_coll_base_reduce_intra_pipeline( const void *sendbuf, void *recvbuf,
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int count, ompi_datatype_t* datatype,
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ompi_op_t* op, int root,
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ompi_communicator_t* comm,
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mca_coll_base_module_t *module,
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uint32_t segsize,
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int max_outstanding_reqs )
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{
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int segcount = count;
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size_t typelng;
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mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
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mca_coll_base_comm_t *data = base_module->base_data;
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OPAL_OUTPUT((ompi_coll_base_framework.framework_output,"coll:base:reduce_intra_pipeline rank %d ss %5d",
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ompi_comm_rank(comm), segsize));
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COLL_BASE_UPDATE_PIPELINE( comm, base_module, root );
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/**
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* Determine number of segments and number of elements
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* sent per operation
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*/
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ompi_datatype_type_size( datatype, &typelng );
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COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
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return ompi_coll_base_reduce_generic( sendbuf, recvbuf, count, datatype,
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op, root, comm, module,
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data->cached_pipeline,
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segcount, max_outstanding_reqs );
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}
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int ompi_coll_base_reduce_intra_binary( const void *sendbuf, void *recvbuf,
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int count, ompi_datatype_t* datatype,
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ompi_op_t* op, int root,
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ompi_communicator_t* comm,
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mca_coll_base_module_t *module,
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uint32_t segsize,
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int max_outstanding_reqs )
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{
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int segcount = count;
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size_t typelng;
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mca_coll_base_module_t *base_module = (mca_coll_base_module_t*) module;
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mca_coll_base_comm_t *data = base_module->base_data;
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OPAL_OUTPUT((ompi_coll_base_framework.framework_output,"coll:base:reduce_intra_binary rank %d ss %5d",
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ompi_comm_rank(comm), segsize));
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COLL_BASE_UPDATE_BINTREE( comm, base_module, root );
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/**
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* Determine number of segments and number of elements
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* sent per operation
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*/
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ompi_datatype_type_size( datatype, &typelng );
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COLL_BASE_COMPUTED_SEGCOUNT( segsize, typelng, segcount );
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return ompi_coll_base_reduce_generic( sendbuf, recvbuf, count, datatype,
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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;
|
|
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 tlb, text, lb, ext;
|
|
char *tmpbuf = NULL;
|
|
|
|
ompi_datatype_get_extent(datatype, &lb, &ext);
|
|
ompi_datatype_get_true_extent(datatype, &tlb, &text);
|
|
|
|
if ((root == rank) && (MPI_IN_PLACE == sendbuf)) {
|
|
tmpbuf = (char *) malloc(text + (ptrdiff_t)(count - 1) * ext);
|
|
if (NULL == tmpbuf) {
|
|
return MPI_ERR_INTERN;
|
|
}
|
|
ompi_datatype_copy_content_same_ddt(datatype, count,
|
|
(char*)tmpbuf,
|
|
(char*)recvbuf);
|
|
use_this_sendbuf = tmpbuf;
|
|
} else if (io_root == rank) {
|
|
tmpbuf = (char *) malloc(text + (ptrdiff_t)(count - 1) * ext);
|
|
if (NULL == tmpbuf) {
|
|
return MPI_ERR_INTERN;
|
|
}
|
|
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; }
|
|
if (MPI_IN_PLACE == sendbuf) {
|
|
free(use_this_sendbuf);
|
|
}
|
|
|
|
} 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; }
|
|
free(use_this_recvbuf);
|
|
}
|
|
}
|
|
|
|
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.
|
|
*/
|
|
|
|
/* copied function (with appropriate renaming) starts here */
|
|
|
|
/*
|
|
* 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 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
|
|
* true_lb, extent, and true extent -- extrapolate for true_ub:
|
|
*
|
|
* 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
|
|
* - true_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
|
|
* - true_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
|
|
* - true_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
|
|
* - true_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-true_lb to
|
|
* MPI_Send. More specifically, the true_lb is positive, so B-true_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 true_lb is negative, so A-true_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 - true_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_datatype_get_extent(dtype, &lb, &extent);
|
|
ompi_datatype_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 - true_lb;
|
|
}
|
|
|
|
if (size > 1) {
|
|
free_buffer = (char*)malloc(true_extent + (count - 1) * extent);
|
|
if (NULL == free_buffer) {
|
|
if (NULL != inplace_temp) {
|
|
free(inplace_temp);
|
|
}
|
|
return OMPI_ERR_OUT_OF_RESOURCE;
|
|
}
|
|
pml_buffer = free_buffer - true_lb;
|
|
}
|
|
|
|
/* 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) {
|
|
err = ompi_datatype_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;
|
|
}
|
|
|
|
/* copied function (with appropriate renaming) ends here */
|