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/*
* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2017 The University of Tennessee and The University
* of Tennessee Research Foundation. All rights
* reserved.
* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2008 Sun Microsystems, Inc. All rights reserved.
* Copyright (c) 2012 Oak Ridge National Labs. All rights reserved.
* Copyright (c) 2012 Sandia National Laboratories. All rights reserved.
* Copyright (c) 2014-2018 Research Organization for Information Science
* and Technology (RIST). All rights reserved.
* Copyright (c) 2022 IBM Corporation. All rights reserved.
* Copyright (c) 2022 Cisco Systems, Inc. All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "ompi_config.h"
#include "coll_basic.h"
#include <stdio.h>
#include <errno.h>
#include "mpi.h"
#include "opal/util/bit_ops.h"
#include "ompi/constants.h"
#include "ompi/mca/coll/coll.h"
#include "ompi/mca/coll/base/coll_tags.h"
#include "ompi/mca/pml/pml.h"
#include "ompi/datatype/ompi_datatype.h"
#include "coll_basic.h"
#include "ompi/op/op.h"
#define COMMUTATIVE_LONG_MSG 8 * 1024 * 1024
/*
* reduce_scatter_block
*
* Function: - reduce then scatter
* Accepts: - same as MPI_Reduce_scatter_block()
* Returns: - MPI_SUCCESS or error code
*
* Algorithm:
* reduce and scatter (needs to be cleaned
* up at some point)
*/
int
mca_coll_basic_reduce_scatter_block_intra(const void *sbuf, void *rbuf, int rcount,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
return ompi_coll_base_reduce_scatter_block_basic_linear(sbuf, rbuf, rcount, dtype, op, comm, module);
}
/*
* reduce_scatter_block_inter
*
* Function: - reduce/scatter operation
* Accepts: - same arguments as MPI_Reduce_scatter()
* Returns: - MPI_SUCCESS or error code
*/
int
mca_coll_basic_reduce_scatter_block_inter(const void *sbuf, void *rbuf, int rcount,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int err, i, rank, root = 0, rsize, lsize;
int totalcounts;
ptrdiff_t gap, span;
char *tmpbuf = NULL, *tmpbuf2 = NULL;
char *lbuf = NULL, *buf;
ompi_request_t *req;
rank = ompi_comm_rank(comm);
rsize = ompi_comm_remote_size(comm);
lsize = ompi_comm_size(comm);
totalcounts = lsize * rcount;
/*
* The following code basically does an interreduce followed by a
* intrascatter. This is implemented by having the roots of each
* group exchange their sbuf. Then, the roots receive the data
* from each of the remote ranks and execute the reduce. When
* this is complete, they have the reduced data available to them
* for doing the scatter. They do this on the local communicator
* associated with the intercommunicator.
*
* Note: There are other ways to implement MPI_Reduce_scatter_block on
* intercommunicators. For example, one could do a MPI_Reduce locally,
* then send the results to the other root which could scatter it.
*
*/
if (rank == root) {
span = opal_datatype_span(&dtype->super, totalcounts, &gap);
tmpbuf = (char *) malloc(2*span);
if (NULL == tmpbuf) {
return OMPI_ERR_OUT_OF_RESOURCE;
}
tmpbuf2 = tmpbuf + span;
lbuf = tmpbuf - gap;
buf = tmpbuf2 - gap;
/* Do a send-recv between the two root procs. to avoid deadlock */
err = MCA_PML_CALL(isend(sbuf, totalcounts, dtype, 0,
MCA_COLL_BASE_TAG_REDUCE_SCATTER,
MCA_PML_BASE_SEND_STANDARD, comm, &req));
if (OMPI_SUCCESS != err) {
goto exit;
}
err = MCA_PML_CALL(recv(lbuf, totalcounts, dtype, 0,
MCA_COLL_BASE_TAG_REDUCE_SCATTER, comm,
MPI_STATUS_IGNORE));
if (OMPI_SUCCESS != err) {
goto exit;
}
err = ompi_request_wait( &req, MPI_STATUS_IGNORE);
if (OMPI_SUCCESS != err) {
goto exit;
}
/* Loop receiving and calling reduction function (C or Fortran)
* The result of this reduction operations is then in
* tmpbuf2.
*/
for (i = 1; i < rsize; i++) {
char *tbuf;
err = MCA_PML_CALL(recv(buf, totalcounts, dtype, i,
MCA_COLL_BASE_TAG_REDUCE_SCATTER, comm,
MPI_STATUS_IGNORE));
if (MPI_SUCCESS != err) {
goto exit;
}
/* Perform the reduction */
ompi_op_reduce(op, lbuf, buf, totalcounts, dtype);
/* swap the buffers */
tbuf = lbuf; lbuf = buf; buf = tbuf;
}
} else {
/* If not root, send data to the root. */
err = MCA_PML_CALL(send(sbuf, totalcounts, dtype, root,
MCA_COLL_BASE_TAG_REDUCE_SCATTER,
MCA_PML_BASE_SEND_STANDARD, comm));
if (OMPI_SUCCESS != err) {
goto exit;
}
}
/* Now do a scatterv on the local communicator */
err = comm->c_local_comm->c_coll->coll_scatter(lbuf, rcount, dtype,
rbuf, rcount, dtype, 0,
comm->c_local_comm,
comm->c_local_comm->c_coll->coll_scatter_module);
exit:
if (NULL != tmpbuf) {
free(tmpbuf);
}
return err;
}
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