1 /* Copyright (c) 2013-2017. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
9 * (C) 2001 by Argonne National Laboratory.
10 * See COPYRIGHT in top-level directory.
13 #include "../colls_private.h"
15 /*****************************************************************************
16 * Function: allgather_mpich_ring
19 * send_buff: send input buffer
20 * send_count: number of elements to send
21 * send_type: data type of elements being sent
22 * recv_buff: receive output buffer
23 * recv_count: number of elements to received
24 * recv_type: data type of elements being received
26 ****************************************************************************/
32 Coll_allgatherv_mpich_ring::allgatherv(void *sendbuf, int sendcount,
33 MPI_Datatype send_type, void *recvbuf,
34 int *recvcounts, int *displs, MPI_Datatype recvtype,
38 char * sbuf = NULL, * rbuf = NULL;
40 int torecv=0, tosend=0, min, rank, comm_size;
44 MPI_Aint recvtype_extent;
45 int right, left, total_count, i;
47 comm_size=comm->size();
49 recvtype_extent= recvtype->get_extent();
51 for (i=0; i<comm_size; i++)
52 total_count += recvcounts[i];
54 if (sendbuf != MPI_IN_PLACE) {
55 /* First, load the "local" version in the recvbuf. */
56 Datatype::copy(sendbuf, sendcount, send_type,
57 ((char *)recvbuf + displs[rank]*recvtype_extent),
58 recvcounts[rank], recvtype);
61 left = (comm_size + rank - 1) % comm_size;
62 right = (rank + 1) % comm_size;
64 torecv = total_count - recvcounts[rank];
65 tosend = total_count - recvcounts[right];
68 for (i = 1; i < comm_size; i++)
69 if (min > recvcounts[i])
71 if (min * recvtype_extent < 32768*8)
72 min = 32768*8 / recvtype_extent;
73 /* Handle the case where the datatype extent is larger than
74 * the pipeline size. */
82 while (tosend || torecv) { /* While we have data to send or receive */
83 sendnow = ((recvcounts[sidx] - soffset) > min) ? min : (recvcounts[sidx] - soffset);
84 recvnow = ((recvcounts[ridx] - roffset) > min) ? min : (recvcounts[ridx] - roffset);
85 sbuf = (char *)recvbuf + ((displs[sidx] + soffset) * recvtype_extent);
86 rbuf = (char *)recvbuf + ((displs[ridx] + roffset) * recvtype_extent);
88 /* Protect against wrap-around of indices */
95 if (not sendnow && not recvnow) {
96 /* Don't do anything. This case is possible if two
97 * consecutive processes contribute 0 bytes each. */
98 } else if (not sendnow) { /* If there's no data to send, just do a recv call */
99 Request::recv(rbuf, recvnow, recvtype, left, COLL_TAG_ALLGATHERV, comm, &status);
102 } else if (not recvnow) { /* If there's no data to receive, just do a send call */
103 Request::send(sbuf, sendnow, recvtype, right, COLL_TAG_ALLGATHERV, comm);
107 else { /* There's data to be sent and received */
108 Request::sendrecv(sbuf, sendnow, recvtype, right, COLL_TAG_ALLGATHERV,
109 rbuf, recvnow, recvtype, left, COLL_TAG_ALLGATHERV,
117 if (soffset == recvcounts[sidx]) {
119 sidx = (sidx + comm_size - 1) % comm_size;
121 if (roffset == recvcounts[ridx]) {
123 ridx = (ridx + comm_size - 1) % comm_size;