+++ /dev/null
-/* Copyright (c) 2013-2014. The SimGrid Team.
- * All rights reserved. */
-
-/* This program is free software; you can redistribute it and/or modify it
- * under the terms of the license (GNU LGPL) which comes with this package. */
-
-#include "colls_private.h"
-
-int smpi_coll_tuned_allreduce_rab_rdb(void *sbuff, void *rbuff, int count,
- MPI_Datatype dtype, MPI_Op op,
- MPI_Comm comm)
-{
- int tag = COLL_TAG_ALLREDUCE;
- unsigned int mask, pof2;
- int dst, newrank, rem, newdst, i,
- send_idx, recv_idx, last_idx, send_cnt, recv_cnt, *cnts, *disps;
- MPI_Aint extent;
- MPI_Status status;
- void *tmp_buf = NULL;
-
- unsigned int nprocs = smpi_comm_size(comm);
- unsigned int rank = smpi_comm_rank(comm);
-
- extent = smpi_datatype_get_extent(dtype);
- tmp_buf = (void *) smpi_get_tmp_sendbuffer(count * extent);
-
- smpi_datatype_copy(sbuff, count, dtype, rbuff, count, dtype);
-
- // find nearest power-of-two less than or equal to comm_size
- pof2 = 1;
- while (pof2 <= nprocs)
- pof2 <<= 1;
- pof2 >>= 1;
-
- rem = nprocs - pof2;
-
- // In the non-power-of-two case, all even-numbered
- // processes of rank < 2*rem send their data to
- // (rank+1). These even-numbered processes no longer
- // participate in the algorithm until the very end. The
- // remaining processes form a nice power-of-two.
-
- if (rank < 2 * rem) {
- // even
- if (rank % 2 == 0) {
-
- smpi_mpi_send(rbuff, count, dtype, rank + 1, tag, comm);
-
- // temporarily set the rank to -1 so that this
- // process does not pariticipate in recursive
- // doubling
- newrank = -1;
- } else // odd
- {
- smpi_mpi_recv(tmp_buf, count, dtype, rank - 1, tag, comm, &status);
- // do the reduction on received data. since the
- // ordering is right, it doesn't matter whether
- // the operation is commutative or not.
- smpi_op_apply(op, tmp_buf, rbuff, &count, &dtype);
-
- // change the rank
- newrank = rank / 2;
- }
- }
-
- else // rank >= 2 * rem
- newrank = rank - rem;
-
- // If op is user-defined or count is less than pof2, use
- // recursive doubling algorithm. Otherwise do a reduce-scatter
- // followed by allgather. (If op is user-defined,
- // derived datatypes are allowed and the user could pass basic
- // datatypes on one process and derived on another as long as
- // the type maps are the same. Breaking up derived
- // datatypes to do the reduce-scatter is tricky, therefore
- // using recursive doubling in that case.)
-
- if (newrank != -1) {
- // do a reduce-scatter followed by allgather. for the
- // reduce-scatter, calculate the count that each process receives
- // and the displacement within the buffer
-
- cnts = (int *) xbt_malloc(pof2 * sizeof(int));
- disps = (int *) xbt_malloc(pof2 * sizeof(int));
-
- for (i = 0; i < (pof2 - 1); i++)
- cnts[i] = count / pof2;
- cnts[pof2 - 1] = count - (count / pof2) * (pof2 - 1);
-
- disps[0] = 0;
- for (i = 1; i < pof2; i++)
- disps[i] = disps[i - 1] + cnts[i - 1];
-
- mask = 0x1;
- send_idx = recv_idx = 0;
- last_idx = pof2;
- while (mask < pof2) {
- newdst = newrank ^ mask;
- // find real rank of dest
- dst = (newdst < rem) ? newdst * 2 + 1 : newdst + rem;
-
- send_cnt = recv_cnt = 0;
- if (newrank < newdst) {
- send_idx = recv_idx + pof2 / (mask * 2);
- for (i = send_idx; i < last_idx; i++)
- send_cnt += cnts[i];
- for (i = recv_idx; i < send_idx; i++)
- recv_cnt += cnts[i];
- } else {
- recv_idx = send_idx + pof2 / (mask * 2);
- for (i = send_idx; i < recv_idx; i++)
- send_cnt += cnts[i];
- for (i = recv_idx; i < last_idx; i++)
- recv_cnt += cnts[i];
- }
-
- // Send data from recvbuf. Recv into tmp_buf
- smpi_mpi_sendrecv((char *) rbuff + disps[send_idx] * extent, send_cnt,
- dtype, dst, tag,
- (char *) tmp_buf + disps[recv_idx] * extent, recv_cnt,
- dtype, dst, tag, comm, &status);
-
- // tmp_buf contains data received in this step.
- // recvbuf contains data accumulated so far
-
- // This algorithm is used only for predefined ops
- // and predefined ops are always commutative.
- smpi_op_apply(op, (char *) tmp_buf + disps[recv_idx] * extent,
- (char *) rbuff + disps[recv_idx] * extent, &recv_cnt, &dtype);
-
- // update send_idx for next iteration
- send_idx = recv_idx;
- mask <<= 1;
-
- // update last_idx, but not in last iteration because the value
- // is needed in the allgather step below.
- if (mask < pof2)
- last_idx = recv_idx + pof2 / mask;
- }
-
- // now do the allgather
-
- mask >>= 1;
- while (mask > 0) {
- newdst = newrank ^ mask;
- // find real rank of dest
- dst = (newdst < rem) ? newdst * 2 + 1 : newdst + rem;
-
- send_cnt = recv_cnt = 0;
- if (newrank < newdst) {
- // update last_idx except on first iteration
- if (mask != pof2 / 2)
- last_idx = last_idx + pof2 / (mask * 2);
-
- recv_idx = send_idx + pof2 / (mask * 2);
- for (i = send_idx; i < recv_idx; i++)
- send_cnt += cnts[i];
- for (i = recv_idx; i < last_idx; i++)
- recv_cnt += cnts[i];
- } else {
- recv_idx = send_idx - pof2 / (mask * 2);
- for (i = send_idx; i < last_idx; i++)
- send_cnt += cnts[i];
- for (i = recv_idx; i < send_idx; i++)
- recv_cnt += cnts[i];
- }
-
- smpi_mpi_sendrecv((char *) rbuff + disps[send_idx] * extent, send_cnt,
- dtype, dst, tag,
- (char *) rbuff + disps[recv_idx] * extent, recv_cnt,
- dtype, dst, tag, comm, &status);
-
- if (newrank > newdst)
- send_idx = recv_idx;
-
- mask >>= 1;
- }
-
- free(cnts);
- free(disps);
-
- }
- // In the non-power-of-two case, all odd-numbered processes of
- // rank < 2 * rem send the result to (rank-1), the ranks who didn't
- // participate above.
-
- if (rank < 2 * rem) {
- if (rank % 2) // odd
- smpi_mpi_send(rbuff, count, dtype, rank - 1, tag, comm);
- else // even
- smpi_mpi_recv(rbuff, count, dtype, rank + 1, tag, comm, &status);
- }
-
- smpi_free_tmp_buffer(tmp_buf);
- return MPI_SUCCESS;
-}
