/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */ /* * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana * University Research and Technology * Corporation. All rights reserved. * Copyright (c) 2004-2012 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) 2009 University of Houston. All rights reserved. * Copyright (c) 2013 Los Alamos National Security, LLC. All rights * reserved. * $COPYRIGHT$ * * Additional copyrights may follow * * $HEADER$ */ #include "ompi_config.h" #include "mpi.h" #include "opal/util/bit_ops.h" #include "ompi/constants.h" #include "ompi/datatype/ompi_datatype.h" #include "ompi/communicator/communicator.h" #include "ompi/mca/coll/coll.h" #include "ompi/mca/coll/base/coll_tags.h" #include "ompi/mca/pml/pml.h" #include "ompi/op/op.h" #include "coll_tuned.h" #include "coll_tuned_topo.h" /* reduce_scatter algorithm variables */ static int coll_tuned_reduce_scatter_algorithm_count = 2; static int coll_tuned_reduce_scatter_forced_algorithm = 0; static int coll_tuned_reduce_scatter_segment_size = 0; static int coll_tuned_reduce_scatter_tree_fanout; static int coll_tuned_reduce_scatter_chain_fanout; /* valid values for coll_tuned_reduce_scatter_forced_algorithm */ static mca_base_var_enum_value_t reduce_scatter_algorithms[] = { {0, "ignore"}, {1, "non-overlapping"}, {2, "recursive_halfing"}, {3, "ring"}, {0, NULL} }; /******************************************************************************* * ompi_coll_tuned_reduce_scatter_intra_nonoverlapping * * This function just calls a reduce to rank 0, followed by an * appropriate scatterv call. */ int ompi_coll_tuned_reduce_scatter_intra_nonoverlapping(void *sbuf, void *rbuf, int *rcounts, 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, size, total_count, *displs = NULL; const int root = 0; char *tmprbuf = NULL, *tmprbuf_free = NULL; rank = ompi_comm_rank(comm); size = ompi_comm_size(comm); OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:reduce_scatter_intra_nonoverlapping, rank %d", rank)); for (i = 0, total_count = 0; i < size; i++) { total_count += rcounts[i]; } /* Reduce to rank 0 (root) and scatterv */ tmprbuf = (char*) rbuf; if (MPI_IN_PLACE == sbuf) { /* rbuf on root (0) is big enough to hold whole data */ if (root == rank) { err = comm->c_coll.coll_reduce (MPI_IN_PLACE, tmprbuf, total_count, dtype, op, root, comm, comm->c_coll.coll_reduce_module); } else { err = comm->c_coll.coll_reduce(tmprbuf, NULL, total_count, dtype, op, root, comm, comm->c_coll.coll_reduce_module); } } else { if (root == rank) { /* We must allocate temporary receive buffer on root to ensure that rbuf is big enough */ ptrdiff_t lb, extent, tlb, textent; ompi_datatype_get_extent(dtype, &lb, &extent); ompi_datatype_get_true_extent(dtype, &tlb, &textent); tmprbuf_free = (char*) malloc(textent + (ptrdiff_t)(total_count - 1) * extent); tmprbuf = tmprbuf_free - lb; } err = comm->c_coll.coll_reduce (sbuf, tmprbuf, total_count, dtype, op, root, comm, comm->c_coll.coll_reduce_module); } if (MPI_SUCCESS != err) { if (NULL != tmprbuf_free) free(tmprbuf_free); return err; } displs = (int*) malloc(size * sizeof(int)); displs[0] = 0; for (i = 1; i < size; i++) { displs[i] = displs[i-1] + rcounts[i-1]; } err = comm->c_coll.coll_scatterv (tmprbuf, rcounts, displs, dtype, rbuf, rcounts[rank], dtype, root, comm, comm->c_coll.coll_scatterv_module); free(displs); if (NULL != tmprbuf_free) free(tmprbuf_free); return err; } /* * Recursive-halving function is (*mostly*) copied from the BASIC coll module. * I have removed the part which handles "large" message sizes * (non-overlapping version of reduce_Scatter). */ /* copied function (with appropriate renaming) starts here */ /* * reduce_scatter_intra_basic_recursivehalving * * Function: - reduce scatter implementation using recursive-halving * algorithm * Accepts: - same as MPI_Reduce_scatter() * Returns: - MPI_SUCCESS or error code * Limitation: - Works only for commutative operations. */ int ompi_coll_tuned_reduce_scatter_intra_basic_recursivehalving(void *sbuf, void *rbuf, int *rcounts, struct ompi_datatype_t *dtype, struct ompi_op_t *op, struct ompi_communicator_t *comm, mca_coll_base_module_t *module) { int i, rank, size, count, err = OMPI_SUCCESS; int tmp_size, remain = 0, tmp_rank, *disps = NULL; ptrdiff_t true_lb, true_extent, lb, extent, buf_size; char *recv_buf = NULL, *recv_buf_free = NULL; char *result_buf = NULL, *result_buf_free = NULL; /* Initialize */ rank = ompi_comm_rank(comm); size = ompi_comm_size(comm); OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:reduce_scatter_intra_basic_recursivehalving, rank %d", rank)); /* Find displacements and the like */ disps = (int*) malloc(sizeof(int) * size); if (NULL == disps) return OMPI_ERR_OUT_OF_RESOURCE; disps[0] = 0; for (i = 0; i < (size - 1); ++i) { disps[i + 1] = disps[i] + rcounts[i]; } count = disps[size - 1] + rcounts[size - 1]; /* short cut the trivial case */ if (0 == count) { free(disps); return OMPI_SUCCESS; } /* get datatype information */ ompi_datatype_get_extent(dtype, &lb, &extent); ompi_datatype_get_true_extent(dtype, &true_lb, &true_extent); buf_size = true_extent + (ptrdiff_t)(count - 1) * extent; /* Handle MPI_IN_PLACE */ if (MPI_IN_PLACE == sbuf) { sbuf = rbuf; } /* Allocate temporary receive buffer. */ recv_buf_free = (char*) malloc(buf_size); recv_buf = recv_buf_free - lb; if (NULL == recv_buf_free) { err = OMPI_ERR_OUT_OF_RESOURCE; goto cleanup; } /* allocate temporary buffer for results */ result_buf_free = (char*) malloc(buf_size); result_buf = result_buf_free - lb; /* copy local buffer into the temporary results */ err = ompi_datatype_sndrcv(sbuf, count, dtype, result_buf, count, dtype); if (OMPI_SUCCESS != err) goto cleanup; /* figure out power of two mapping: grow until larger than comm size, then go back one, to get the largest power of two less than comm size */ tmp_size = opal_next_poweroftwo (size); tmp_size >>= 1; remain = size - tmp_size; /* If comm size is not a power of two, have the first "remain" procs with an even rank send to rank + 1, leaving a power of two procs to do the rest of the algorithm */ if (rank < 2 * remain) { if ((rank & 1) == 0) { err = MCA_PML_CALL(send(result_buf, count, dtype, rank + 1, MCA_COLL_BASE_TAG_REDUCE_SCATTER, MCA_PML_BASE_SEND_STANDARD, comm)); if (OMPI_SUCCESS != err) goto cleanup; /* we don't participate from here on out */ tmp_rank = -1; } else { err = MCA_PML_CALL(recv(recv_buf, count, dtype, rank - 1, MCA_COLL_BASE_TAG_REDUCE_SCATTER, comm, MPI_STATUS_IGNORE)); /* integrate their results into our temp results */ ompi_op_reduce(op, recv_buf, result_buf, count, dtype); /* adjust rank to be the bottom "remain" ranks */ tmp_rank = rank / 2; } } else { /* just need to adjust rank to show that the bottom "even remain" ranks dropped out */ tmp_rank = rank - remain; } /* For ranks not kicked out by the above code, perform the recursive halving */ if (tmp_rank >= 0) { int *tmp_disps = NULL, *tmp_rcounts = NULL; int mask, send_index, recv_index, last_index; /* recalculate disps and rcounts to account for the special "remainder" processes that are no longer doing anything */ tmp_rcounts = (int*) malloc(tmp_size * sizeof(int)); if (NULL == tmp_rcounts) { err = OMPI_ERR_OUT_OF_RESOURCE; goto cleanup; } tmp_disps = (int*) malloc(tmp_size * sizeof(int)); if (NULL == tmp_disps) { free(tmp_rcounts); err = OMPI_ERR_OUT_OF_RESOURCE; goto cleanup; } for (i = 0 ; i < tmp_size ; ++i) { if (i < remain) { /* need to include old neighbor as well */ tmp_rcounts[i] = rcounts[i * 2 + 1] + rcounts[i * 2]; } else { tmp_rcounts[i] = rcounts[i + remain]; } } tmp_disps[0] = 0; for (i = 0; i < tmp_size - 1; ++i) { tmp_disps[i + 1] = tmp_disps[i] + tmp_rcounts[i]; } /* do the recursive halving communication. Don't use the dimension information on the communicator because I think the information is invalidated by our "shrinking" of the communicator */ mask = tmp_size >> 1; send_index = recv_index = 0; last_index = tmp_size; while (mask > 0) { int tmp_peer, peer, send_count, recv_count; struct ompi_request_t *request; tmp_peer = tmp_rank ^ mask; peer = (tmp_peer < remain) ? tmp_peer * 2 + 1 : tmp_peer + remain; /* figure out if we're sending, receiving, or both */ send_count = recv_count = 0; if (tmp_rank < tmp_peer) { send_index = recv_index + mask; for (i = send_index ; i < last_index ; ++i) { send_count += tmp_rcounts[i]; } for (i = recv_index ; i < send_index ; ++i) { recv_count += tmp_rcounts[i]; } } else { recv_index = send_index + mask; for (i = send_index ; i < recv_index ; ++i) { send_count += tmp_rcounts[i]; } for (i = recv_index ; i < last_index ; ++i) { recv_count += tmp_rcounts[i]; } } /* actual data transfer. Send from result_buf, receive into recv_buf */ if (recv_count > 0) { err = MCA_PML_CALL(irecv(recv_buf + (ptrdiff_t)tmp_disps[recv_index] * extent, recv_count, dtype, peer, MCA_COLL_BASE_TAG_REDUCE_SCATTER, comm, &request)); if (OMPI_SUCCESS != err) { free(tmp_rcounts); free(tmp_disps); goto cleanup; } } if (send_count > 0) { err = MCA_PML_CALL(send(result_buf + (ptrdiff_t)tmp_disps[send_index] * extent, send_count, dtype, peer, MCA_COLL_BASE_TAG_REDUCE_SCATTER, MCA_PML_BASE_SEND_STANDARD, comm)); if (OMPI_SUCCESS != err) { free(tmp_rcounts); free(tmp_disps); goto cleanup; } } /* if we received something on this step, push it into the results buffer */ if (recv_count > 0) { err = ompi_request_wait(&request, MPI_STATUS_IGNORE); if (OMPI_SUCCESS != err) { free(tmp_rcounts); free(tmp_disps); goto cleanup; } ompi_op_reduce(op, recv_buf + (ptrdiff_t)tmp_disps[recv_index] * extent, result_buf + (ptrdiff_t)tmp_disps[recv_index] * extent, recv_count, dtype); } /* update for next iteration */ send_index = recv_index; last_index = recv_index + mask; mask >>= 1; } /* copy local results from results buffer into real receive buffer */ if (0 != rcounts[rank]) { err = ompi_datatype_sndrcv(result_buf + disps[rank] * extent, rcounts[rank], dtype, rbuf, rcounts[rank], dtype); if (OMPI_SUCCESS != err) { free(tmp_rcounts); free(tmp_disps); goto cleanup; } } free(tmp_rcounts); free(tmp_disps); } /* Now fix up the non-power of two case, by having the odd procs send the even procs the proper results */ if (rank < (2 * remain)) { if ((rank & 1) == 0) { if (rcounts[rank]) { err = MCA_PML_CALL(recv(rbuf, rcounts[rank], dtype, rank + 1, MCA_COLL_BASE_TAG_REDUCE_SCATTER, comm, MPI_STATUS_IGNORE)); if (OMPI_SUCCESS != err) goto cleanup; } } else { if (rcounts[rank - 1]) { err = MCA_PML_CALL(send(result_buf + disps[rank - 1] * extent, rcounts[rank - 1], dtype, rank - 1, MCA_COLL_BASE_TAG_REDUCE_SCATTER, MCA_PML_BASE_SEND_STANDARD, comm)); if (OMPI_SUCCESS != err) goto cleanup; } } } cleanup: if (NULL != disps) free(disps); if (NULL != recv_buf_free) free(recv_buf_free); if (NULL != result_buf_free) free(result_buf_free); return err; } /* copied function (with appropriate renaming) ends here */ /* * ompi_coll_tuned_reduce_scatter_intra_ring * * Function: Ring algorithm for reduce_scatter operation * Accepts: Same as MPI_Reduce_scatter() * Returns: MPI_SUCCESS or error code * * Description: Implements ring algorithm for reduce_scatter: * the block sizes defined in rcounts are exchanged and 8 updated until they reach proper destination. * Algorithm requires 2 * max(rcounts) extra buffering * * Limitations: The algorithm DOES NOT preserve order of operations so it * can be used only for commutative operations. * Example on 5 nodes: * Initial state * # 0 1 2 3 4 * [00] [10] -> [20] [30] [40] * [01] [11] [21] -> [31] [41] * [02] [12] [22] [32] -> [42] * -> [03] [13] [23] [33] [43] --> .. * [04] -> [14] [24] [34] [44] * * COMPUTATION PHASE * Step 0: rank r sends block (r-1) to rank (r+1) and * receives block (r+1) from rank (r-1) [with wraparound]. * # 0 1 2 3 4 * [00] [10] [10+20] -> [30] [40] * [01] [11] [21] [21+31] -> [41] * -> [02] [12] [22] [32] [32+42] -->.. * [43+03] -> [13] [23] [33] [43] * [04] [04+14] -> [24] [34] [44] * * Step 1: * # 0 1 2 3 4 * [00] [10] [10+20] [10+20+30] -> [40] * -> [01] [11] [21] [21+31] [21+31+41] -> * [32+42+02] -> [12] [22] [32] [32+42] * [03] [43+03+13] -> [23] [33] [43] * [04] [04+14] [04+14+24] -> [34] [44] * * Step 2: * # 0 1 2 3 4 * -> [00] [10] [10+20] [10+20+30] [10+20+30+40] -> * [21+31+41+01]-> [11] [21] [21+31] [21+31+41] * [32+42+02] [32+42+02+12]-> [22] [32] [32+42] * [03] [43+03+13] [43+03+13+23]-> [33] [43] * [04] [04+14] [04+14+24] [04+14+24+34] -> [44] * * Step 3: * # 0 1 2 3 4 * [10+20+30+40+00] [10] [10+20] [10+20+30] [10+20+30+40] * [21+31+41+01] [21+31+41+01+11] [21] [21+31] [21+31+41] * [32+42+02] [32+42+02+12] [32+42+02+12+22] [32] [32+42] * [03] [43+03+13] [43+03+13+23] [43+03+13+23+33] [43] * [04] [04+14] [04+14+24] [04+14+24+34] [04+14+24+34+44] * DONE :) * */ int ompi_coll_tuned_reduce_scatter_intra_ring(void *sbuf, void *rbuf, int *rcounts, struct ompi_datatype_t *dtype, struct ompi_op_t *op, struct ompi_communicator_t *comm, mca_coll_base_module_t *module) { int ret, line, rank, size, i, k, recv_from, send_to, total_count, max_block_count; int inbi, *displs = NULL; char *tmpsend = NULL, *tmprecv = NULL, *accumbuf = NULL, *accumbuf_free = NULL; char *inbuf_free[2] = {NULL, NULL}, *inbuf[2] = {NULL, NULL}; ptrdiff_t true_lb, true_extent, lb, extent, max_real_segsize; ompi_request_t *reqs[2] = {NULL, NULL}; size_t typelng; size = ompi_comm_size(comm); rank = ompi_comm_rank(comm); OPAL_OUTPUT((ompi_coll_tuned_stream, "coll:tuned:reduce_scatter_intra_ring rank %d, size %d", rank, size)); /* Determine the maximum number of elements per node, corresponding block size, and displacements array. */ displs = (int*) malloc(size * sizeof(int)); if (NULL == displs) { ret = -1; line = __LINE__; goto error_hndl; } displs[0] = 0; total_count = rcounts[0]; max_block_count = rcounts[0]; for (i = 1; i < size; i++) { displs[i] = total_count; total_count += rcounts[i]; if (max_block_count < rcounts[i]) max_block_count = rcounts[i]; } /* Special case for size == 1 */ if (1 == size) { if (MPI_IN_PLACE != sbuf) { ret = ompi_datatype_copy_content_same_ddt(dtype, total_count, (char*)rbuf, (char*)sbuf); if (ret < 0) { line = __LINE__; goto error_hndl; } } free(displs); return MPI_SUCCESS; } /* Allocate and initialize temporary buffers, we need: - a temporary buffer to perform reduction (size total_count) since rbuf can be of rcounts[rank] size. - up to two temporary buffers used for communication/computation overlap. */ ret = ompi_datatype_get_extent(dtype, &lb, &extent); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } ret = ompi_datatype_get_true_extent(dtype, &true_lb, &true_extent); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } ret = ompi_datatype_type_size( dtype, &typelng); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } max_real_segsize = true_extent + (ptrdiff_t)(max_block_count - 1) * extent; accumbuf_free = (char*)malloc(true_extent + (ptrdiff_t)(total_count - 1) * extent); if (NULL == accumbuf_free) { ret = -1; line = __LINE__; goto error_hndl; } accumbuf = accumbuf_free - lb; inbuf_free[0] = (char*)malloc(max_real_segsize); if (NULL == inbuf_free[0]) { ret = -1; line = __LINE__; goto error_hndl; } inbuf[0] = inbuf_free[0] - lb; if (size > 2) { inbuf_free[1] = (char*)malloc(max_real_segsize); if (NULL == inbuf_free[1]) { ret = -1; line = __LINE__; goto error_hndl; } inbuf[1] = inbuf_free[1] - lb; } /* Handle MPI_IN_PLACE for size > 1 */ if (MPI_IN_PLACE == sbuf) { sbuf = rbuf; } ret = ompi_datatype_copy_content_same_ddt(dtype, total_count, accumbuf, (char*)sbuf); if (ret < 0) { line = __LINE__; goto error_hndl; } /* Computation loop */ /* For each of the remote nodes: - post irecv for block (r-2) from (r-1) with wrap around - send block (r-1) to (r+1) - in loop for every step k = 2 .. n - post irecv for block (r - 1 + n - k) % n - wait on block (r + n - k) % n to arrive - compute on block (r + n - k ) % n - send block (r + n - k) % n - wait on block (r) - compute on block (r) - copy block (r) to rbuf Note that we must be careful when computing the begining of buffers and for send operations and computation we must compute the exact block size. */ send_to = (rank + 1) % size; recv_from = (rank + size - 1) % size; inbi = 0; /* Initialize first receive from the neighbor on the left */ ret = MCA_PML_CALL(irecv(inbuf[inbi], max_block_count, dtype, recv_from, MCA_COLL_BASE_TAG_REDUCE_SCATTER, comm, &reqs[inbi])); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } tmpsend = accumbuf + (ptrdiff_t)displs[recv_from] * extent; ret = MCA_PML_CALL(send(tmpsend, rcounts[recv_from], dtype, send_to, MCA_COLL_BASE_TAG_REDUCE_SCATTER, MCA_PML_BASE_SEND_STANDARD, comm)); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } for (k = 2; k < size; k++) { const int prevblock = (rank + size - k) % size; inbi = inbi ^ 0x1; /* Post irecv for the current block */ ret = MCA_PML_CALL(irecv(inbuf[inbi], max_block_count, dtype, recv_from, MCA_COLL_BASE_TAG_REDUCE_SCATTER, comm, &reqs[inbi])); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } /* Wait on previous block to arrive */ ret = ompi_request_wait(&reqs[inbi ^ 0x1], MPI_STATUS_IGNORE); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } /* Apply operation on previous block: result goes to rbuf rbuf[prevblock] = inbuf[inbi ^ 0x1] (op) rbuf[prevblock] */ tmprecv = accumbuf + (ptrdiff_t)displs[prevblock] * extent; ompi_op_reduce(op, inbuf[inbi ^ 0x1], tmprecv, rcounts[prevblock], dtype); /* send previous block to send_to */ ret = MCA_PML_CALL(send(tmprecv, rcounts[prevblock], dtype, send_to, MCA_COLL_BASE_TAG_REDUCE_SCATTER, MCA_PML_BASE_SEND_STANDARD, comm)); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } } /* Wait on the last block to arrive */ ret = ompi_request_wait(&reqs[inbi], MPI_STATUS_IGNORE); if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; } /* Apply operation on the last block (my block) rbuf[rank] = inbuf[inbi] (op) rbuf[rank] */ tmprecv = accumbuf + (ptrdiff_t)displs[rank] * extent; ompi_op_reduce(op, inbuf[inbi], tmprecv, rcounts[rank], dtype); /* Copy result from tmprecv to rbuf */ ret = ompi_datatype_copy_content_same_ddt(dtype, rcounts[rank], (char *)rbuf, tmprecv); if (ret < 0) { line = __LINE__; goto error_hndl; } if (NULL != displs) free(displs); if (NULL != accumbuf_free) free(accumbuf_free); if (NULL != inbuf_free[0]) free(inbuf_free[0]); if (NULL != inbuf_free[1]) free(inbuf_free[1]); return MPI_SUCCESS; error_hndl: OPAL_OUTPUT((ompi_coll_tuned_stream, "%s:%4d\tRank %d Error occurred %d\n", __FILE__, line, rank, ret)); if (NULL != displs) free(displs); if (NULL != accumbuf_free) free(accumbuf_free); if (NULL != inbuf_free[0]) free(inbuf_free[0]); if (NULL != inbuf_free[1]) free(inbuf_free[1]); return ret; } /** * The following are used by dynamic and forced rules * * publish details of each algorithm and if its forced/fixed/locked in * as you add methods/algorithms you must update this and the query/map routines * * this routine is called by the component only * this makes sure that the mca parameters are set to their initial values and * perms module does not call this they call the forced_getvalues routine * instead */ int ompi_coll_tuned_reduce_scatter_intra_check_forced_init (coll_tuned_force_algorithm_mca_param_indices_t *mca_param_indices) { mca_base_var_enum_t *new_enum; ompi_coll_tuned_forced_max_algorithms[REDUCESCATTER] = coll_tuned_reduce_scatter_algorithm_count; (void) mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version, "reduce_scatter_algorithm_count", "Number of reduce_scatter algorithms available", MCA_BASE_VAR_TYPE_INT, NULL, 0, MCA_BASE_VAR_FLAG_DEFAULT_ONLY, OPAL_INFO_LVL_5, MCA_BASE_VAR_SCOPE_CONSTANT, &coll_tuned_reduce_scatter_algorithm_count); /* MPI_T: This variable should eventually be bound to a communicator */ coll_tuned_reduce_scatter_forced_algorithm = 0; (void) mca_base_var_enum_create("coll_tuned_reduce_scatter_algorithms", reduce_scatter_algorithms, &new_enum); mca_param_indices->algorithm_param_index = mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version, "reduce_scatter_algorithm", "Which reduce reduce_scatter algorithm is used. Can be locked down to choice of: 0 ignore, 1 non-overlapping (Reduce + Scatterv), 2 recursive halving, 3 ring", MCA_BASE_VAR_TYPE_INT, new_enum, 0, 0, OPAL_INFO_LVL_5, MCA_BASE_VAR_SCOPE_READONLY, &coll_tuned_reduce_scatter_forced_algorithm); OBJ_RELEASE(new_enum); if (mca_param_indices->algorithm_param_index < 0) { return mca_param_indices->algorithm_param_index; } coll_tuned_reduce_scatter_segment_size = 0; mca_param_indices->segsize_param_index = mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version, "reduce_scatter_algorithm_segmentsize", "Segment size in bytes used by default for reduce_scatter algorithms. Only has meaning if algorithm is forced and supports segmenting. 0 bytes means no segmentation.", MCA_BASE_VAR_TYPE_INT, NULL, 0, 0, OPAL_INFO_LVL_5, MCA_BASE_VAR_SCOPE_READONLY, &coll_tuned_reduce_scatter_segment_size); coll_tuned_reduce_scatter_tree_fanout = ompi_coll_tuned_init_tree_fanout; /* get system wide default */ mca_param_indices->tree_fanout_param_index = mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version, "reduce_scatter_algorithm_tree_fanout", "Fanout for n-tree used for reduce_scatter algorithms. Only has meaning if algorithm is forced and supports n-tree topo based operation.", MCA_BASE_VAR_TYPE_INT, NULL, 0, 0, OPAL_INFO_LVL_5, MCA_BASE_VAR_SCOPE_READONLY, &coll_tuned_reduce_scatter_tree_fanout); coll_tuned_reduce_scatter_chain_fanout = ompi_coll_tuned_init_chain_fanout; /* get system wide default */ mca_param_indices->chain_fanout_param_index = mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version, "reduce_scatter_algorithm_chain_fanout", "Fanout for chains used for reduce_scatter algorithms. Only has meaning if algorithm is forced and supports chain topo based operation.", MCA_BASE_VAR_TYPE_INT, NULL, 0, 0, OPAL_INFO_LVL_5, MCA_BASE_VAR_SCOPE_READONLY, &coll_tuned_reduce_scatter_chain_fanout); return (MPI_SUCCESS); } int ompi_coll_tuned_reduce_scatter_intra_do_forced(void *sbuf, void* rbuf, int *rcounts, struct ompi_datatype_t *dtype, struct ompi_op_t *op, struct ompi_communicator_t *comm, mca_coll_base_module_t *module) { mca_coll_tuned_module_t *tuned_module = (mca_coll_tuned_module_t*) module; mca_coll_tuned_comm_t *data = tuned_module->tuned_data; OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:reduce_scatter_intra_do_forced selected algorithm %d", data->user_forced[REDUCESCATTER].algorithm)); switch (data->user_forced[REDUCESCATTER].algorithm) { case (0): return ompi_coll_tuned_reduce_scatter_intra_dec_fixed (sbuf, rbuf, rcounts, dtype, op, comm, module); case (1): return ompi_coll_tuned_reduce_scatter_intra_nonoverlapping(sbuf, rbuf, rcounts, dtype, op, comm, module); case (2): return ompi_coll_tuned_reduce_scatter_intra_basic_recursivehalving(sbuf, rbuf, rcounts, dtype, op, comm, module); case (3): return ompi_coll_tuned_reduce_scatter_intra_ring (sbuf, rbuf, rcounts, dtype, op, comm, module); default: OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:reduce_scatter_intra_do_forced attempt to select algorithm %d when only 0-%d is valid?", data->user_forced[REDUCESCATTER].algorithm, ompi_coll_tuned_forced_max_algorithms[REDUCESCATTER])); return (MPI_ERR_ARG); } /* switch */ } int ompi_coll_tuned_reduce_scatter_intra_do_this(void *sbuf, void* rbuf, int *rcounts, struct ompi_datatype_t *dtype, struct ompi_op_t *op, struct ompi_communicator_t *comm, mca_coll_base_module_t *module, int algorithm, int faninout, int segsize) { OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:reduce_scatter_intra_do_this selected algorithm %d topo faninout %d segsize %d", algorithm, faninout, segsize)); switch (algorithm) { case (0): return ompi_coll_tuned_reduce_scatter_intra_dec_fixed (sbuf, rbuf, rcounts, dtype, op, comm, module); case (1): return ompi_coll_tuned_reduce_scatter_intra_nonoverlapping(sbuf, rbuf, rcounts, dtype, op, comm, module); case (2): return ompi_coll_tuned_reduce_scatter_intra_basic_recursivehalving(sbuf, rbuf, rcounts, dtype, op, comm, module); case (3): return ompi_coll_tuned_reduce_scatter_intra_ring (sbuf, rbuf, rcounts, dtype, op, comm, module); default: OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:reduce_scatter_intra_do_this attempt to select algorithm %d when only 0-%d is valid?", algorithm, ompi_coll_tuned_forced_max_algorithms[REDUCESCATTER])); return (MPI_ERR_ARG); } /* switch */ }