1 /*
2 * Copyright (C) by Argonne National Laboratory
3 * See COPYRIGHT in top-level directory
4 */
5
6 #include "mpiimpl.h"
7
8 /* Intercommunicator Allreduce
9 *
10 * We first do intracommunicator reduces to rank 0 on left and right
11 * groups, then an exchange between left and right rank 0, and finally
12 * intracommunicator broadcasts from rank 0 on left and right
13 * group.
14 */
15
MPIR_Allreduce_inter_reduce_exchange_bcast(const void * sendbuf,void * recvbuf,int count,MPI_Datatype datatype,MPI_Op op,MPIR_Comm * comm_ptr,MPIR_Errflag_t * errflag)16 int MPIR_Allreduce_inter_reduce_exchange_bcast(const void *sendbuf, void *recvbuf, int
17 count, MPI_Datatype datatype, MPI_Op op,
18 MPIR_Comm * comm_ptr, MPIR_Errflag_t * errflag)
19 {
20 int mpi_errno;
21 int mpi_errno_ret = MPI_SUCCESS;
22 MPI_Aint true_extent, true_lb, extent;
23 void *tmp_buf = NULL;
24 MPIR_Comm *newcomm_ptr = NULL;
25 MPIR_CHKLMEM_DECL(1);
26
27 if (comm_ptr->rank == 0) {
28 MPIR_Type_get_true_extent_impl(datatype, &true_lb, &true_extent);
29 MPIR_Datatype_get_extent_macro(datatype, extent);
30 MPIR_CHKLMEM_MALLOC(tmp_buf, void *, count * (MPL_MAX(extent, true_extent)), mpi_errno,
31 "temporary buffer", MPL_MEM_BUFFER);
32 /* adjust for potential negative lower bound in datatype */
33 tmp_buf = (void *) ((char *) tmp_buf - true_lb);
34 }
35
36 /* Get the local intracommunicator */
37 if (!comm_ptr->local_comm)
38 MPII_Setup_intercomm_localcomm(comm_ptr);
39
40 newcomm_ptr = comm_ptr->local_comm;
41
42 /* Do a local reduce on this intracommunicator */
43 mpi_errno = MPIR_Reduce(sendbuf, tmp_buf, count, datatype, op, 0, newcomm_ptr, errflag);
44 if (mpi_errno) {
45 /* for communication errors, just record the error but continue */
46 *errflag =
47 MPIX_ERR_PROC_FAILED ==
48 MPIR_ERR_GET_CLASS(mpi_errno) ? MPIR_ERR_PROC_FAILED : MPIR_ERR_OTHER;
49 MPIR_ERR_SET(mpi_errno, *errflag, "**fail");
50 MPIR_ERR_ADD(mpi_errno_ret, mpi_errno);
51 }
52
53 /* Do a exchange between local and remote rank 0 on this intercommunicator */
54 if (comm_ptr->rank == 0) {
55 mpi_errno = MPIC_Sendrecv(tmp_buf, count, datatype, 0, MPIR_REDUCE_TAG,
56 recvbuf, count, datatype, 0, MPIR_REDUCE_TAG,
57 comm_ptr, MPI_STATUS_IGNORE, errflag);
58 if (mpi_errno) {
59 /* for communication errors, just record the error but continue */
60 *errflag =
61 MPIX_ERR_PROC_FAILED ==
62 MPIR_ERR_GET_CLASS(mpi_errno) ? MPIR_ERR_PROC_FAILED : MPIR_ERR_OTHER;
63 MPIR_ERR_SET(mpi_errno, *errflag, "**fail");
64 MPIR_ERR_ADD(mpi_errno_ret, mpi_errno);
65 }
66 }
67
68 /* Do a local broadcast on this intracommunicator */
69 mpi_errno = MPIR_Bcast(recvbuf, count, datatype, 0, newcomm_ptr, errflag);
70 if (mpi_errno) {
71 /* for communication errors, just record the error but continue */
72 *errflag =
73 MPIX_ERR_PROC_FAILED ==
74 MPIR_ERR_GET_CLASS(mpi_errno) ? MPIR_ERR_PROC_FAILED : MPIR_ERR_OTHER;
75 MPIR_ERR_SET(mpi_errno, *errflag, "**fail");
76 MPIR_ERR_ADD(mpi_errno_ret, mpi_errno);
77 }
78
79 fn_exit:
80 MPIR_CHKLMEM_FREEALL();
81 if (mpi_errno_ret)
82 mpi_errno = mpi_errno_ret;
83 else if (*errflag != MPIR_ERR_NONE)
84 MPIR_ERR_SET(mpi_errno, *errflag, "**coll_fail");
85
86 return mpi_errno;
87
88 fn_fail:
89 goto fn_exit;
90 }
91