963 строки
36 KiB
C
963 строки
36 KiB
C
/* -*- Mode: C; c-basic-offset:2 ; indent-tabs-mode:nil -*- */
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/*
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* Copyright (c) 2006 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) 2006 The Technical University of Chemnitz. All
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* rights reserved.
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* Copyright (c) 2013-2015 Los Alamos National Security, LLC. All rights
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* reserved.
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* Copyright (c) 2014-2018 Research Organization for Information Science
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* and Technology (RIST). All rights reserved.
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* Copyright (c) 2017 IBM Corporation. All rights reserved.
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* Copyright (c) 2018 FUJITSU LIMITED. 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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* Author(s): Torsten Hoefler <htor@cs.indiana.edu>
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*
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*/
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#include "ompi_config.h"
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#include "opal/align.h"
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#include "opal/util/bit_ops.h"
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#include "ompi/op/op.h"
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#include "nbc_internal.h"
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static inline int red_sched_binomial (int rank, int p, int root, const void *sendbuf, void *redbuf, char tmpredbuf, int count, MPI_Datatype datatype,
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MPI_Op op, char inplace, NBC_Schedule *schedule, void *tmpbuf);
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static inline int red_sched_chain (int rank, int p, int root, const void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype,
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MPI_Op op, int ext, size_t size, NBC_Schedule *schedule, void *tmpbuf, int fragsize);
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static inline int red_sched_linear (int rank, int rsize, int root, const void *sendbuf, void *recvbuf, void *tmpbuf, int count, MPI_Datatype datatype,
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MPI_Op op, NBC_Schedule *schedule);
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static inline int red_sched_redscat_gather(
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int rank, int comm_size, int root, const void *sbuf, void *rbuf,
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char tmpredbuf, int count, MPI_Datatype datatype, MPI_Op op, char inplace,
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NBC_Schedule *schedule, void *tmp_buf, struct ompi_communicator_t *comm);
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#ifdef NBC_CACHE_SCHEDULE
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/* tree comparison function for schedule cache */
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int NBC_Reduce_args_compare(NBC_Reduce_args *a, NBC_Reduce_args *b, void *param) {
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if ((a->sendbuf == b->sendbuf) &&
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(a->recvbuf == b->recvbuf) &&
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(a->count == b->count) &&
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(a->datatype == b->datatype) &&
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(a->op == b->op) &&
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(a->root == b->root)) {
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return 0;
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}
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if (a->sendbuf < b->sendbuf) {
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return -1;
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}
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return 1;
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}
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#endif
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/* the non-blocking reduce */
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static int nbc_reduce_init(const void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype,
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MPI_Op op, int root, struct ompi_communicator_t *comm, ompi_request_t ** request,
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struct mca_coll_base_module_2_3_0_t *module, bool persistent) {
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int rank, p, res, segsize;
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size_t size;
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MPI_Aint ext;
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NBC_Schedule *schedule;
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char *redbuf=NULL, inplace;
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void *tmpbuf;
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char tmpredbuf = 0;
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enum { NBC_RED_BINOMIAL, NBC_RED_CHAIN, NBC_RED_REDSCAT_GATHER} alg;
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ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module;
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ptrdiff_t span, gap;
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NBC_IN_PLACE(sendbuf, recvbuf, inplace);
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rank = ompi_comm_rank (comm);
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p = ompi_comm_size (comm);
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res = ompi_datatype_type_extent(datatype, &ext);
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if (MPI_SUCCESS != res) {
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NBC_Error("MPI Error in ompi_datatype_type_extent() (%i)", res);
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return res;
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}
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res = ompi_datatype_type_size(datatype, &size);
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if (MPI_SUCCESS != res) {
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NBC_Error("MPI Error in ompi_datatype_type_size() (%i)", res);
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return res;
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}
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/* only one node -> copy data */
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if (1 == p && (!persistent || inplace)) {
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if (!inplace) {
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res = NBC_Copy (sendbuf, count, datatype, recvbuf, count, datatype, comm);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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return res;
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}
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}
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return nbc_get_noop_request(persistent, request);
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}
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span = opal_datatype_span(&datatype->super, count, &gap);
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/* algorithm selection */
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int nprocs_pof2 = opal_next_poweroftwo(p) >> 1;
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if (libnbc_ireduce_algorithm == 0) {
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if (ompi_op_is_commute(op) && p > 2 && count >= nprocs_pof2) {
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alg = NBC_RED_REDSCAT_GATHER;
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} else if (p > 4 || size * count < 65536 || !ompi_op_is_commute(op)) {
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alg = NBC_RED_BINOMIAL;
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} else {
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alg = NBC_RED_CHAIN;
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}
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} else {
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if (libnbc_ireduce_algorithm == 1) {
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alg = NBC_RED_CHAIN;
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} else if (libnbc_ireduce_algorithm == 2) {
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alg = NBC_RED_BINOMIAL;
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} else if (libnbc_ireduce_algorithm == 3 && ompi_op_is_commute(op) && p > 2 && count >= nprocs_pof2) {
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alg = NBC_RED_REDSCAT_GATHER;
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} else {
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alg = NBC_RED_CHAIN;
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}
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}
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/* allocate temporary buffers */
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if (alg == NBC_RED_REDSCAT_GATHER || alg == NBC_RED_BINOMIAL) {
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if (rank == root) {
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/* root reduces in receive buffer */
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tmpbuf = malloc(span);
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redbuf = recvbuf;
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} else {
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/* recvbuf may not be valid on non-root nodes */
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ptrdiff_t span_align = OPAL_ALIGN(span, datatype->super.align, ptrdiff_t);
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tmpbuf = malloc(span_align + span);
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redbuf = (char *)span_align - gap;
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tmpredbuf = 1;
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}
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} else {
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tmpbuf = malloc (span);
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segsize = 16384/2;
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}
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if (OPAL_UNLIKELY(NULL == tmpbuf)) {
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return OMPI_ERR_OUT_OF_RESOURCE;
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}
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#ifdef NBC_CACHE_SCHEDULE
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NBC_Reduce_args *args, *found, search;
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/* search schedule in communicator specific tree */
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search.sendbuf = sendbuf;
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search.recvbuf = recvbuf;
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search.count = count;
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search.datatype = datatype;
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search.op = op;
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search.root = root;
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found = (NBC_Reduce_args *) hb_tree_search ((hb_tree *) libnbc_module->NBC_Dict[NBC_REDUCE], &search);
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if (NULL == found) {
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#endif
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schedule = OBJ_NEW(NBC_Schedule);
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if (OPAL_UNLIKELY(NULL == schedule)) {
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free(tmpbuf);
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return OMPI_ERR_OUT_OF_RESOURCE;
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}
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if (p == 1) {
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res = NBC_Sched_copy ((void *)sendbuf, false, count, datatype,
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recvbuf, false, count, datatype, schedule, false);
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} else {
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switch(alg) {
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case NBC_RED_BINOMIAL:
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res = red_sched_binomial(rank, p, root, sendbuf, redbuf, tmpredbuf, count, datatype, op, inplace, schedule, tmpbuf);
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break;
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case NBC_RED_CHAIN:
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res = red_sched_chain(rank, p, root, sendbuf, recvbuf, count, datatype, op, ext, size, schedule, tmpbuf, segsize);
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break;
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case NBC_RED_REDSCAT_GATHER:
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res = red_sched_redscat_gather(rank, p, root, sendbuf, redbuf, tmpredbuf, count, datatype, op, inplace, schedule, tmpbuf, comm);
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break;
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}
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}
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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OBJ_RELEASE(schedule);
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free(tmpbuf);
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return res;
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}
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res = NBC_Sched_commit(schedule);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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OBJ_RELEASE(schedule);
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free(tmpbuf);
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return res;
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}
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#ifdef NBC_CACHE_SCHEDULE
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/* save schedule to tree */
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args = (NBC_Reduce_args *) malloc (sizeof (args));
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if (NULL != args) {
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args->sendbuf = sendbuf;
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args->recvbuf = recvbuf;
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args->count = count;
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args->datatype = datatype;
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args->op = op;
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args->root = root;
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args->schedule = schedule;
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res = hb_tree_insert ((hb_tree *) libnbc_module->NBC_Dict[NBC_REDUCE], args, args, 0);
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if (0 == res) {
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OBJ_RETAIN(schedule);
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/* increase number of elements for Reduce */
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if (++libnbc_module->NBC_Dict_size[NBC_REDUCE] > NBC_SCHED_DICT_UPPER) {
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NBC_SchedCache_dictwipe ((hb_tree *) libnbc_module->NBC_Dict[NBC_REDUCE],
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&libnbc_module->NBC_Dict_size[NBC_REDUCE]);
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}
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} else {
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NBC_Error("error in dict_insert() (%i)", res);
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free (args);
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}
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}
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} else {
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/* found schedule */
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schedule = found->schedule;
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OBJ_RETAIN(schedule);
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}
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#endif
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res = NBC_Schedule_request(schedule, comm, libnbc_module, persistent, request, tmpbuf);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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OBJ_RELEASE(schedule);
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free(tmpbuf);
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return res;
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}
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return OMPI_SUCCESS;
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}
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int ompi_coll_libnbc_ireduce(const void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype,
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MPI_Op op, int root, struct ompi_communicator_t *comm, ompi_request_t ** request,
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struct mca_coll_base_module_2_3_0_t *module) {
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int res = nbc_reduce_init(sendbuf, recvbuf, count, datatype, op, root,
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comm, request, module, false);
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if (OPAL_LIKELY(OMPI_SUCCESS != res)) {
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return res;
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}
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res = NBC_Start(*(ompi_coll_libnbc_request_t **)request);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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NBC_Return_handle (*(ompi_coll_libnbc_request_t **)request);
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*request = &ompi_request_null.request;
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return res;
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}
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return OMPI_SUCCESS;
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}
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static int nbc_reduce_inter_init(const void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype,
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MPI_Op op, int root, struct ompi_communicator_t *comm, ompi_request_t ** request,
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struct mca_coll_base_module_2_3_0_t *module, bool persistent) {
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int rank, res, rsize;
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NBC_Schedule *schedule;
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ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module;
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ptrdiff_t span, gap;
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void *tmpbuf;
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rank = ompi_comm_rank (comm);
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rsize = ompi_comm_remote_size (comm);
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span = opal_datatype_span(&datatype->super, count, &gap);
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tmpbuf = malloc (span);
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if (OPAL_UNLIKELY(NULL == tmpbuf)) {
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return OMPI_ERR_OUT_OF_RESOURCE;
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}
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schedule = OBJ_NEW(NBC_Schedule);
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if (OPAL_UNLIKELY(NULL == schedule)) {
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free(tmpbuf);
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return OMPI_ERR_OUT_OF_RESOURCE;
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}
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res = red_sched_linear (rank, rsize, root, sendbuf, recvbuf, (void *)(-gap), count, datatype, op, schedule);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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OBJ_RELEASE(schedule);
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free(tmpbuf);
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return OMPI_ERR_OUT_OF_RESOURCE;
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}
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res = NBC_Sched_commit(schedule);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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OBJ_RELEASE(schedule);
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free(tmpbuf);
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return res;
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}
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res = NBC_Schedule_request(schedule, comm, libnbc_module, persistent, request, tmpbuf);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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OBJ_RELEASE(schedule);
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free(tmpbuf);
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return OMPI_ERR_OUT_OF_RESOURCE;
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}
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return OMPI_SUCCESS;
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}
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int ompi_coll_libnbc_ireduce_inter(const void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype,
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MPI_Op op, int root, struct ompi_communicator_t *comm, ompi_request_t ** request,
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struct mca_coll_base_module_2_3_0_t *module) {
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int res = nbc_reduce_inter_init(sendbuf, recvbuf, count, datatype, op, root,
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comm, request, module, false);
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if (OPAL_LIKELY(OMPI_SUCCESS != res)) {
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return res;
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}
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res = NBC_Start(*(ompi_coll_libnbc_request_t **)request);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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NBC_Return_handle (*(ompi_coll_libnbc_request_t **)request);
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*request = &ompi_request_null.request;
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return res;
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}
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return OMPI_SUCCESS;
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}
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/* binomial reduce
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* if op is not commutative, reduce on rank 0, and then send the result to root rank
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*
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* working principle:
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* - each node gets a virtual rank vrank
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* - the 'root' node get vrank 0
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* - node 0 gets the vrank of the 'root'
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* - all other ranks stay identical (they do not matter)
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*
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* Algorithm:
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* pairwise exchange
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* round r:
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* grp = rank % 2^r
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* if grp == 0: receive from rank + 2^(r-1) if it exists and reduce value
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* if grp == 1: send to rank - 2^(r-1) and exit function
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*
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* do this for R=log_2(p) rounds
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*
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*/
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#define RANK2VRANK(rank, vrank, root) \
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{ \
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vrank = rank; \
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if (rank == 0) vrank = root; \
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if (rank == root) vrank = 0; \
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}
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#define VRANK2RANK(rank, vrank, root) \
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{ \
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rank = vrank; \
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if (vrank == 0) rank = root; \
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if (vrank == root) rank = 0; \
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}
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static inline int red_sched_binomial (int rank, int p, int root, const void *sendbuf, void *redbuf, char tmpredbuf, int count, MPI_Datatype datatype,
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MPI_Op op, char inplace, NBC_Schedule *schedule, void *tmpbuf) {
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int vroot, vrank, vpeer, peer, res, maxr;
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char *rbuf, *lbuf, *buf;
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int tmprbuf, tmplbuf;
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ptrdiff_t gap;
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(void)opal_datatype_span(&datatype->super, count, &gap);
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if (ompi_op_is_commute(op)) {
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vroot = root;
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} else {
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vroot = 0;
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}
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RANK2VRANK(rank, vrank, vroot);
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maxr = (int)ceil((log((double)p)/LOG2));
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if (rank != root) {
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inplace = 0;
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}
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/* ensure the result ends up in redbuf on vrank 0 */
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if (0 == (maxr%2)) {
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rbuf = (void *)(-gap);
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tmprbuf = true;
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lbuf = redbuf;
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tmplbuf = tmpredbuf;
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} else {
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lbuf = (void *)(-gap);
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tmplbuf = true;
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rbuf = redbuf;
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tmprbuf = tmpredbuf;
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if (inplace) {
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res = NBC_Sched_copy(rbuf, false, count, datatype,
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((char *)tmpbuf)-gap, false, count, datatype,
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schedule, true);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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return res;
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}
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}
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}
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for (int r = 1, firstred = 1 ; r <= maxr ; ++r) {
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if ((vrank % (1 << r)) == 0) {
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/* we have to receive this round */
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vpeer = vrank + (1 << (r - 1));
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VRANK2RANK(peer, vpeer, vroot)
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if (peer < p) {
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int tbuf;
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/* we have to wait until we have the data */
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res = NBC_Sched_recv (rbuf, tmprbuf, count, datatype, peer, schedule, true);
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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return res;
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}
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/* perform the reduce in my local buffer */
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/* this cannot be done until tmpbuf is unused :-( so barrier after the op */
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if (firstred && !inplace) {
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/* perform the reduce with the senbuf */
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res = NBC_Sched_op (sendbuf, false, rbuf, tmprbuf, count, datatype, op, schedule, true);
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firstred = 0;
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} else {
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/* perform the reduce in my local buffer */
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res = NBC_Sched_op (lbuf, tmplbuf, rbuf, tmprbuf, count, datatype, op, schedule, true);
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}
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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return res;
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}
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/* swap left and right buffers */
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buf = rbuf; rbuf = lbuf ; lbuf = buf;
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tbuf = tmprbuf; tmprbuf = tmplbuf; tmplbuf = tbuf;
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}
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} else {
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/* we have to send this round */
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vpeer = vrank - (1 << (r - 1));
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VRANK2RANK(peer, vpeer, vroot)
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if (firstred && !inplace) {
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/* we have to use the sendbuf in the first round .. */
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res = NBC_Sched_send (sendbuf, false, count, datatype, peer, schedule, false);
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} else {
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/* and the redbuf in all remaining rounds */
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res = NBC_Sched_send (lbuf, tmplbuf, count, datatype, peer, schedule, false);
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}
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if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
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return res;
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}
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/* leave the game */
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break;
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}
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}
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/* send to root if vroot ! root */
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if (vroot != root) {
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if (0 == rank) {
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res = NBC_Sched_send (redbuf, tmpredbuf, count, datatype, root, schedule, false);
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} else if (root == rank) {
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res = NBC_Sched_recv (redbuf, tmpredbuf, count, datatype, vroot, schedule, false);
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}
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}
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return OMPI_SUCCESS;
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}
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/* chain send ... */
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static inline int red_sched_chain (int rank, int p, int root, const void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype,
|
|
MPI_Op op, int ext, size_t size, NBC_Schedule *schedule, void *tmpbuf, int fragsize) {
|
|
int res, vrank, rpeer, speer, numfrag, fragcount, thiscount;
|
|
long offset;
|
|
|
|
RANK2VRANK(rank, vrank, root);
|
|
VRANK2RANK(rpeer, vrank+1, root);
|
|
VRANK2RANK(speer, vrank-1, root);
|
|
|
|
if (0 == count) {
|
|
return OMPI_SUCCESS;
|
|
}
|
|
|
|
numfrag = count * size / fragsize;
|
|
if ((count * size) % fragsize != 0) {
|
|
numfrag++;
|
|
}
|
|
|
|
fragcount = count / numfrag;
|
|
|
|
for (int fragnum = 0 ; fragnum < numfrag ; ++fragnum) {
|
|
offset = fragnum * fragcount * ext;
|
|
thiscount = fragcount;
|
|
if(fragnum == numfrag - 1) {
|
|
/* last fragment may not be full */
|
|
thiscount = count - fragcount * fragnum;
|
|
}
|
|
|
|
/* last node does not recv */
|
|
if (vrank != p-1) {
|
|
if (vrank == 0 && sendbuf != recvbuf) {
|
|
res = NBC_Sched_recv ((char *)recvbuf+offset, false, thiscount, datatype, rpeer, schedule, true);
|
|
} else {
|
|
res = NBC_Sched_recv ((char *)offset, true, thiscount, datatype, rpeer, schedule, true);
|
|
}
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
|
|
/* root reduces into receivebuf */
|
|
if(vrank == 0) {
|
|
if (sendbuf != recvbuf) {
|
|
res = NBC_Sched_op ((char *) sendbuf + offset, false, (char *) recvbuf + offset, false,
|
|
thiscount, datatype, op, schedule, true);
|
|
} else {
|
|
res = NBC_Sched_op ((char *)offset, true, (char *) recvbuf + offset, false,
|
|
thiscount, datatype, op, schedule, true);
|
|
}
|
|
} else {
|
|
res = NBC_Sched_op ((char *) sendbuf + offset, false, (char *) offset, true, thiscount,
|
|
datatype, op, schedule, true);
|
|
}
|
|
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
}
|
|
|
|
/* root does not send */
|
|
if (vrank != 0) {
|
|
/* rank p-1 has to send out of sendbuffer :) */
|
|
/* the barrier here seems awkward but isn't!!!! */
|
|
if (vrank == p-1) {
|
|
res = NBC_Sched_send ((char *) sendbuf + offset, false, thiscount, datatype, speer, schedule, true);
|
|
} else {
|
|
res = NBC_Sched_send ((char *) offset, true, thiscount, datatype, speer, schedule, true);
|
|
}
|
|
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
}
|
|
}
|
|
|
|
return OMPI_SUCCESS;
|
|
}
|
|
|
|
/* simple linear algorithm for intercommunicators */
|
|
static inline int red_sched_linear (int rank, int rsize, int root, const void *sendbuf, void *recvbuf, void *tmpbuf, int count, MPI_Datatype datatype,
|
|
MPI_Op op, NBC_Schedule *schedule) {
|
|
int res;
|
|
char *rbuf, *lbuf, *buf;
|
|
int tmprbuf, tmplbuf;
|
|
|
|
if (0 == count) {
|
|
return OMPI_SUCCESS;
|
|
}
|
|
|
|
if (MPI_ROOT == root) {
|
|
/* ensure the result ends up in recvbuf */
|
|
if (0 == (rsize%2)) {
|
|
lbuf = tmpbuf;
|
|
tmplbuf = true;
|
|
rbuf = recvbuf;
|
|
tmprbuf = false;
|
|
} else {
|
|
rbuf = tmpbuf;
|
|
tmprbuf = true;
|
|
lbuf = recvbuf;
|
|
tmplbuf = false;
|
|
}
|
|
|
|
res = NBC_Sched_recv (lbuf, tmplbuf, count, datatype, 0, schedule, false);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
|
|
for (int peer = 1 ; peer < rsize ; ++peer) {
|
|
res = NBC_Sched_recv (rbuf, tmprbuf, count, datatype, peer, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
|
|
res = NBC_Sched_op (lbuf, tmplbuf, rbuf, tmprbuf, count, datatype, op, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
/* swap left and right buffers */
|
|
buf = rbuf; rbuf = lbuf ; lbuf = buf;
|
|
tmprbuf ^= 1; tmplbuf ^= 1;
|
|
}
|
|
} else if (MPI_PROC_NULL != root) {
|
|
res = NBC_Sched_send (sendbuf, false, count, datatype, root, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
}
|
|
|
|
return OMPI_SUCCESS;
|
|
}
|
|
|
|
/*
|
|
* red_sched_redscat_gather:
|
|
*
|
|
* 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.
|
|
*
|
|
* 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)
|
|
*
|
|
* Schedule length (rounds): O(\log(p))
|
|
* Recommendations: root = 0, otherwise it is required additional steps
|
|
* in the root process.
|
|
*/
|
|
static inline int red_sched_redscat_gather(
|
|
int rank, int comm_size, int root, const void *sbuf, void *rbuf,
|
|
char tmpredbuf, int count, MPI_Datatype datatype, MPI_Op op, char inplace,
|
|
NBC_Schedule *schedule, void *tmp_buf, struct ompi_communicator_t *comm)
|
|
{
|
|
int res = OMPI_SUCCESS;
|
|
int *rindex = NULL, *rcount = NULL, *sindex = NULL, *scount = NULL;
|
|
|
|
/* 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) */
|
|
if (nsteps < 1) {
|
|
/* This case never happens (for comm_size < 2 other algorithms are used) */
|
|
return OMPI_ERR_NOT_SUPPORTED;
|
|
}
|
|
int nprocs_pof2 = 1 << nsteps; /* flp2(comm_size) */
|
|
|
|
ptrdiff_t lb, extent;
|
|
ompi_datatype_get_extent(datatype, &lb, &extent);
|
|
|
|
if ((rank != root) || !inplace) {
|
|
res = NBC_Sched_copy((char *)sbuf, false, count, datatype,
|
|
rbuf, tmpredbuf, count, datatype, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { 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
|
|
*/
|
|
res = NBC_Sched_send(rbuf, tmpredbuf, count_lhalf, datatype, rank - 1,
|
|
schedule, false);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
res = NBC_Sched_recv((char *)tmp_buf + (ptrdiff_t)count_lhalf * extent,
|
|
false, count_rhalf, datatype, rank - 1, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
res = NBC_Sched_op((char *)tmp_buf + (ptrdiff_t)count_lhalf * extent,
|
|
false, (char *)rbuf + (ptrdiff_t)count_lhalf * extent,
|
|
tmpredbuf, count_rhalf, datatype, op, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
/* Send the right half to the left neighbor */
|
|
res = NBC_Sched_send((char *)rbuf + (ptrdiff_t)count_lhalf * extent,
|
|
tmpredbuf, count_rhalf, datatype, rank - 1, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
/* This process does not participate 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
|
|
*/
|
|
res = NBC_Sched_send((char *)rbuf + (ptrdiff_t)count_lhalf * extent,
|
|
tmpredbuf, count_rhalf, datatype, rank + 1, schedule, false);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
res = NBC_Sched_recv((char *)tmp_buf, false, count_lhalf, datatype, rank + 1,
|
|
schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
res = NBC_Sched_op(tmp_buf, false, rbuf, tmpredbuf, count_lhalf,
|
|
datatype, op, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
/* Recv the right half from the right neighbor */
|
|
res = NBC_Sched_recv((char *)rbuf + (ptrdiff_t)count_lhalf * extent,
|
|
tmpredbuf, count_rhalf, datatype, rank + 1, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { 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) {
|
|
res = 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 */
|
|
res = NBC_Sched_send((char *)rbuf + (ptrdiff_t)sindex[step] * extent,
|
|
tmpredbuf, scount[step], datatype, dest, schedule, false);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
res = NBC_Sched_recv((char *)tmp_buf + (ptrdiff_t)rindex[step] * extent,
|
|
false, rcount[step], datatype, dest, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
/* Local reduce: rbuf[] = tmp_buf[] <op> rbuf[] */
|
|
res = NBC_Sched_op((char *)tmp_buf + (ptrdiff_t)rindex[step] * extent,
|
|
false, (char *)rbuf + (ptrdiff_t)rindex[step] * extent,
|
|
tmpredbuf, rcount[step], datatype, op, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
|
|
/* 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;
|
|
}
|
|
|
|
res = NBC_Sched_recv(rbuf, tmpredbuf, rcount[nsteps - 1], datatype,
|
|
0, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
vrank = 0;
|
|
|
|
} else if (vrank == 0) {
|
|
/* Send a data to the root */
|
|
res = NBC_Sched_send(rbuf, tmpredbuf, rcount[nsteps - 1], datatype,
|
|
root, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { 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 */
|
|
|
|
res = NBC_Sched_send((char *)rbuf + (ptrdiff_t)rindex[step] * extent,
|
|
tmpredbuf, rcount[step], datatype, dest, schedule, false);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
break;
|
|
} else {
|
|
/* Recv and continue */
|
|
res = NBC_Sched_recv((char *)rbuf + (ptrdiff_t)sindex[step] * extent,
|
|
tmpredbuf, scount[step], datatype, dest, schedule, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) { goto cleanup_and_return; }
|
|
}
|
|
step--;
|
|
}
|
|
}
|
|
|
|
cleanup_and_return:
|
|
if (NULL != rindex)
|
|
free(rindex);
|
|
if (NULL != sindex)
|
|
free(sindex);
|
|
if (NULL != rcount)
|
|
free(rcount);
|
|
if (NULL != scount)
|
|
free(scount);
|
|
return res;
|
|
}
|
|
|
|
int ompi_coll_libnbc_reduce_init(const void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype,
|
|
MPI_Op op, int root, struct ompi_communicator_t *comm, MPI_Info info, ompi_request_t ** request,
|
|
struct mca_coll_base_module_2_3_0_t *module) {
|
|
int res = nbc_reduce_init(sendbuf, recvbuf, count, datatype, op, root,
|
|
comm, request, module, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
|
|
return OMPI_SUCCESS;
|
|
}
|
|
|
|
int ompi_coll_libnbc_reduce_inter_init(const void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype,
|
|
MPI_Op op, int root, struct ompi_communicator_t *comm, MPI_Info info, ompi_request_t ** request,
|
|
struct mca_coll_base_module_2_3_0_t *module) {
|
|
int res = nbc_reduce_inter_init(sendbuf, recvbuf, count, datatype, op, root,
|
|
comm, request, module, true);
|
|
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
|
|
return res;
|
|
}
|
|
|
|
return OMPI_SUCCESS;
|
|
}
|