/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */ /* * Copyright (c) 2009-2012 Oak Ridge National Laboratory. All rights reserved. * Copyright (c) 2009-2012 Mellanox Technologies. All rights reserved. * Copyright (c) 2013-2014 Los Alamos National Security, LLC. All rights * reserved. * $COPYRIGHT$ * * Additional copyrights may follow * * $HEADER$ */ /** @file */ #include "ompi_config.h" #include #include "ompi/constants.h" #include "opal/threads/mutex.h" #include "ompi/communicator/communicator.h" #include "ompi/mca/coll/coll.h" #include "ompi/mca/bcol/bcol.h" #include "opal/sys/atomic.h" #include "coll_ml.h" #include "coll_ml_select.h" #include "coll_ml_allocation.h" static int mca_coll_ml_allgather_small_unpack_data(mca_coll_ml_collective_operation_progress_t *coll_op) { bool rcontig = coll_op->full_message.recv_data_continguous; int n_ranks_in_comm = ompi_comm_size(OP_ML_MODULE(coll_op)->comm); void *dest = (void *)((uintptr_t)coll_op->full_message.dest_user_addr + (uintptr_t)coll_op->full_message.n_bytes_delivered); void *src = (void *)((uintptr_t)coll_op->fragment_data.buffer_desc->data_addr + (size_t)coll_op->variable_fn_params.rbuf_offset); if (rcontig) { memcpy(dest, src, n_ranks_in_comm * coll_op->full_message.n_bytes_scheduled); } else { mca_coll_ml_convertor_unpack(src, n_ranks_in_comm * coll_op->full_message.n_bytes_scheduled, &coll_op->fragment_data.message_descriptor->recv_convertor); } return OMPI_SUCCESS; } static inline void copy_data (mca_coll_ml_collective_operation_progress_t *coll_op, rank_properties_t *rank_props, int soffset) { bool rcontig = coll_op->fragment_data.message_descriptor->recv_data_continguous; size_t total_bytes = coll_op->fragment_data.message_descriptor->n_bytes_total; size_t pack_len = coll_op->fragment_data.fragment_size; int doffset = rank_props->rank; void *dest, *src; src = (void *) ((uintptr_t)coll_op->fragment_data.buffer_desc->data_addr + (size_t)coll_op->variable_fn_params.rbuf_offset + soffset * pack_len); if (rcontig) { dest = (void *) ((uintptr_t) coll_op->full_message.dest_user_addr + (uintptr_t) coll_op->fragment_data.offset_into_user_buffer + doffset * total_bytes); memcpy(dest, src, pack_len); } else { size_t position; opal_convertor_t *recv_convertor = &coll_op->fragment_data.message_descriptor->recv_convertor; position = (size_t) coll_op->fragment_data.offset_into_user_buffer + doffset * total_bytes; opal_convertor_set_position(recv_convertor, &position); mca_coll_ml_convertor_unpack(src, pack_len, recv_convertor); } } static int mca_coll_ml_allgather_noncontiguous_unpack_data(mca_coll_ml_collective_operation_progress_t *coll_op) { int i, j, n_level_one_sbgps; size_t soffset; mca_coll_ml_topology_t *topo_info = coll_op->coll_schedule->topo_info; sub_group_params_t *array_of_all_subgroup_ranks = topo_info->array_of_all_subgroups; n_level_one_sbgps = array_of_all_subgroup_ranks->level_one_index; for (i = 0 ; i < n_level_one_sbgps; i++) { /* determine where in the source buffer the data can be found */ soffset = array_of_all_subgroup_ranks[i].index_of_first_element; for (j = 0 ; j < array_of_all_subgroup_ranks[i].n_ranks; j++, ++soffset) { copy_data (coll_op, array_of_all_subgroup_ranks[i].rank_data + j, soffset); } } return OMPI_SUCCESS; } /* Allgather dependencies seem easy, everyone needs to work from the "bottom up". * Following Pasha, I too will put the simplest dependencies graph and change it later * when we add hierarchy. Basically, allgather has the same dependency profile as the * sequential broadcast except that there is only a single ordering of tasks. */ static int mca_coll_ml_allgather_task_setup(mca_coll_ml_collective_operation_progress_t *coll_op) { int fn_idx, h_level, my_index, root; mca_sbgp_base_module_t *sbgp; mca_coll_ml_topology_t *topo = coll_op->coll_schedule->topo_info; fn_idx = coll_op->sequential_routine.current_active_bcol_fn; h_level = coll_op->coll_schedule->component_functions[fn_idx].h_level; sbgp = topo->component_pairs[h_level]. subgroup_module; my_index = sbgp->my_index; /* In the case of allgather, the local leader is always the root */ root = 0; if (my_index == root) { coll_op->variable_fn_params.root_flag = true; coll_op->variable_fn_params.root_route = NULL; } else { coll_op->variable_fn_params.root_flag = false; coll_op->variable_fn_params.root_route = &topo->route_vector[root]; } return OMPI_SUCCESS; } static int mca_coll_ml_allgather_frag_progress(mca_coll_ml_collective_operation_progress_t *coll_op) { /* local variables */ int ret; size_t frag_len, dt_size; void *buf; mca_bcol_base_payload_buffer_desc_t *src_buffer_desc; mca_coll_ml_collective_operation_progress_t *new_op; mca_coll_ml_module_t *ml_module = OP_ML_MODULE(coll_op); bool scontig = coll_op->fragment_data.message_descriptor->send_data_continguous; ompi_datatype_type_size(coll_op->variable_fn_params.dtype, &dt_size); /* Keep the pipeline filled with fragments */ while (coll_op->fragment_data.message_descriptor->n_active < coll_op->fragment_data.message_descriptor->pipeline_depth) { /* If an active fragment happens to have completed the collective during * a hop into the progress engine, then don't launch a new fragment, * instead break and return. */ if (coll_op->fragment_data.message_descriptor->n_bytes_scheduled == coll_op->fragment_data.message_descriptor->n_bytes_total) { break; } /* Get an ml buffer */ src_buffer_desc = mca_coll_ml_alloc_buffer(ml_module); if (NULL == src_buffer_desc) { /* If there exist outstanding fragments, then break out * and let an active fragment deal with this later, * there are no buffers available. */ if (0 < coll_op->fragment_data.message_descriptor->n_active) { return OMPI_SUCCESS; } else { /* The fragment is already on list and * the we still have no ml resources * Return busy */ if (coll_op->pending & REQ_OUT_OF_MEMORY) { ML_VERBOSE(10,("Out of resources %p", coll_op)); return OMPI_ERR_TEMP_OUT_OF_RESOURCE; } coll_op->pending |= REQ_OUT_OF_MEMORY; opal_list_append(&((OP_ML_MODULE(coll_op))->waiting_for_memory_list), (opal_list_item_t *)coll_op); ML_VERBOSE(10,("Out of resources %p adding to pending queue", coll_op)); return OMPI_ERR_TEMP_OUT_OF_RESOURCE; } } /* Get a new collective descriptor and initialize it */ new_op = mca_coll_ml_alloc_op_prog_single_frag_dag(ml_module, ml_module->coll_ml_allgather_functions[ML_SMALL_DATA_ALLGATHER], coll_op->fragment_data.message_descriptor->src_user_addr, coll_op->fragment_data.message_descriptor->dest_user_addr, coll_op->fragment_data.message_descriptor->n_bytes_total, coll_op->fragment_data.message_descriptor->n_bytes_scheduled); new_op->fragment_data.current_coll_op = coll_op->fragment_data.current_coll_op; new_op->fragment_data.message_descriptor = coll_op->fragment_data.message_descriptor; /* set the task setup callback */ new_op->sequential_routine.seq_task_setup = mca_coll_ml_allgather_task_setup; /* MCA_COLL_IBOFFLOAD_SET_ML_BUFFER_INFO(new_op, src_buffer_desc->buffer_index, src_buffer_desc); */ /* We need this address for pointer arithmetic in memcpy */ buf = coll_op->fragment_data.message_descriptor->src_user_addr; if (!scontig) { frag_len = ml_module->small_message_thresholds[BCOL_ALLGATHER]; mca_coll_ml_convertor_get_send_frag_size( ml_module, &frag_len, coll_op->fragment_data.message_descriptor); mca_coll_ml_convertor_pack( (void *) ((uintptr_t) src_buffer_desc->data_addr + frag_len * coll_op->coll_schedule->topo_info->hier_layout_info[0].offset + frag_len * coll_op->coll_schedule->topo_info->hier_layout_info[0].level_one_index), frag_len, &coll_op->fragment_data.message_descriptor->send_convertor); } else { /* calculate new frag length, there are some issues here */ frag_len = (coll_op->fragment_data.message_descriptor->n_bytes_total - coll_op->fragment_data.message_descriptor->n_bytes_scheduled < coll_op->fragment_data.fragment_size ? coll_op->fragment_data.message_descriptor->n_bytes_total - coll_op->fragment_data.message_descriptor->n_bytes_scheduled : coll_op->fragment_data.fragment_size); /* everybody copies in, based on the new values */ memcpy((void *) ((uintptr_t)src_buffer_desc->data_addr + frag_len * new_op->coll_schedule->topo_info->hier_layout_info[0].offset + frag_len * new_op->coll_schedule->topo_info->hier_layout_info[0].level_one_index), (void *) ((uintptr_t) buf + (uintptr_t) coll_op->fragment_data.message_descriptor->n_bytes_scheduled), frag_len); } new_op->variable_fn_params.sbuf = (void *) src_buffer_desc->data_addr; new_op->variable_fn_params.rbuf = (void *) src_buffer_desc->data_addr; /* update the number of bytes scheduled */ new_op->fragment_data.message_descriptor->n_bytes_scheduled += frag_len; /* everyone needs an unpack function */ new_op->process_fn = mca_coll_ml_allgather_noncontiguous_unpack_data; new_op->fragment_data.fragment_size = frag_len; new_op->fragment_data.buffer_desc = src_buffer_desc; /* Setup fragment specific data */ ++(new_op->fragment_data.message_descriptor->n_active); ML_VERBOSE(10, ("Start more, My index %d ", new_op->fragment_data.buffer_desc->buffer_index)); /* this is a bit buggy */ ML_SET_VARIABLE_PARAMS_BCAST( new_op, OP_ML_MODULE(new_op), frag_len /* yes, we have consistent units, so this makes sense */, MPI_BYTE /* we fragment according to buffer size * we don't reduce the data thus we needn't * keep "whole" datatypes, we may freely * fragment without regard for multiples * of any specific datatype */, src_buffer_desc, 0, 0, frag_len, src_buffer_desc->data_addr); /* initialize first coll */ ret = new_op->sequential_routine.seq_task_setup(new_op); if (OMPI_SUCCESS != ret) { ML_VERBOSE(3, ("Fragment failed to initialize itself")); return ret; } new_op->variable_fn_params.buffer_size = frag_len; new_op->variable_fn_params.hier_factor = coll_op->variable_fn_params.hier_factor; new_op->variable_fn_params.root = 0; MCA_COLL_ML_SET_NEW_FRAG_ORDER_INFO(new_op); /* append this collective !! */ OPAL_THREAD_LOCK(&(mca_coll_ml_component.sequential_collectives_mutex)); opal_list_append(&mca_coll_ml_component.sequential_collectives, (opal_list_item_t *)new_op); OPAL_THREAD_UNLOCK(&(mca_coll_ml_component.sequential_collectives_mutex)); } return OMPI_SUCCESS; } static inline __opal_attribute_always_inline__ int mca_coll_ml_allgather_start (void *sbuf, int scount, struct ompi_datatype_t *sdtype, void* rbuf, int rcount, struct ompi_datatype_t *rdtype, struct ompi_communicator_t *comm, mca_coll_base_module_t *module, ompi_request_t **req) { size_t pack_len, sdt_size; int ret, n_fragments = 1, comm_size; mca_coll_ml_topology_t *topo_info; mca_bcol_base_payload_buffer_desc_t *src_buffer_desc; mca_coll_ml_component_t *cm = &mca_coll_ml_component; mca_coll_ml_collective_operation_progress_t *coll_op; mca_coll_ml_module_t *ml_module = (mca_coll_ml_module_t *) module; ptrdiff_t lb, extent; bool scontig, rcontig, in_place = false; /* check for in place setting */ if (MPI_IN_PLACE == sbuf) { in_place = true; sdtype = rdtype; scount = rcount; } /* scontig could be != to rcontig */ scontig = ompi_datatype_is_contiguous_memory_layout(sdtype, scount); rcontig = ompi_datatype_is_contiguous_memory_layout(rdtype, rcount); comm_size = ompi_comm_size(comm); ML_VERBOSE(10, ("Starting allgather")); assert(NULL != sdtype); /* Calculate size of the data, * at this stage, only contiguous data is supported */ /* this is valid for allagther */ ompi_datatype_type_size(sdtype, &sdt_size); pack_len = scount * sdt_size; if (in_place) { sbuf = (char *) rbuf + ompi_comm_rank(comm) * pack_len; } /* Allocate collective schedule and pack message */ /* this is the total ending message size that will need to fit in the ml-buffer */ if (pack_len <= (size_t) ml_module->small_message_thresholds[BCOL_ALLGATHER]) { /* The len of the message can not be larger than ML buffer size */ ML_VERBOSE(10, ("Single frag %d %d %d", pack_len, comm_size, ml_module->payload_block->size_buffer)); assert(pack_len * comm_size <= ml_module->payload_block->size_buffer); src_buffer_desc = mca_coll_ml_alloc_buffer(ml_module); while (NULL == src_buffer_desc) { opal_progress(); src_buffer_desc = mca_coll_ml_alloc_buffer(ml_module); } /* change 1 */ coll_op = mca_coll_ml_alloc_op_prog_single_frag_dag(ml_module, ml_module->coll_ml_allgather_functions[ML_SMALL_DATA_ALLGATHER], sbuf, rbuf, pack_len, 0 /* offset for first pack */); MCA_COLL_IBOFFLOAD_SET_ML_BUFFER_INFO(coll_op, src_buffer_desc->buffer_index, src_buffer_desc); coll_op->fragment_data.current_coll_op = ML_SMALL_DATA_ALLGATHER; /* task setup callback function */ coll_op->sequential_routine.seq_task_setup = mca_coll_ml_allgather_task_setup; /* change 2 */ if (!scontig) { coll_op->full_message.n_bytes_scheduled = mca_coll_ml_convertor_prepare(sdtype, scount, sbuf, &coll_op->full_message.send_convertor, MCA_COLL_ML_NET_STREAM_SEND); mca_coll_ml_convertor_pack( (void *) ((uintptr_t) src_buffer_desc->data_addr + pack_len * (coll_op->coll_schedule->topo_info->hier_layout_info[0].offset + coll_op->coll_schedule->topo_info->hier_layout_info[0].level_one_index)), pack_len, &coll_op->full_message.send_convertor); } else { /* change 3 */ memcpy((void *)((uintptr_t) src_buffer_desc->data_addr + pack_len * (coll_op->coll_schedule->topo_info->hier_layout_info[0].offset + coll_op->coll_schedule->topo_info->hier_layout_info[0].level_one_index)), sbuf, pack_len); coll_op->full_message.n_bytes_scheduled = pack_len; } if (!rcontig) { mca_coll_ml_convertor_prepare(rdtype, rcount * comm_size, rbuf, &coll_op->full_message.recv_convertor, MCA_COLL_ML_NET_STREAM_RECV); } if (coll_op->coll_schedule->topo_info->ranks_contiguous) { coll_op->process_fn = mca_coll_ml_allgather_small_unpack_data; } else { coll_op->process_fn = mca_coll_ml_allgather_noncontiguous_unpack_data; } /* whole ml-buffer is used to send AND receive */ coll_op->variable_fn_params.sbuf = (void *) src_buffer_desc->data_addr; coll_op->variable_fn_params.rbuf = (void *) src_buffer_desc->data_addr; /* we can set the initial offset here */ coll_op->variable_fn_params.sbuf_offset = 0; coll_op->variable_fn_params.rbuf_offset = 0; coll_op->variable_fn_params.count = scount; coll_op->fragment_data.fragment_size = coll_op->full_message.n_bytes_scheduled; /* For small CINCO, we may use the native datatype */ coll_op->variable_fn_params.dtype = sdtype; coll_op->variable_fn_params.buffer_size = pack_len; coll_op->variable_fn_params.root = 0; } else if (cm->enable_fragmentation || pack_len * comm_size < (1 << 20)) { /* calculate the number of fragments and the size of each frag */ size_t n_dts_per_frag, frag_len; int pipeline_depth = mca_coll_ml_component.pipeline_depth; /* Calculate the number of fragments required for this message careful watch the integer division !*/ frag_len = (pack_len <= (size_t) ml_module->small_message_thresholds[BCOL_ALLGATHER] ? pack_len : (size_t) ml_module->small_message_thresholds[BCOL_ALLGATHER]); n_dts_per_frag = frag_len / sdt_size; n_fragments = (pack_len + sdt_size * n_dts_per_frag - 1) / (sdt_size * n_dts_per_frag); pipeline_depth = (n_fragments < pipeline_depth ? n_fragments : pipeline_depth); src_buffer_desc = mca_coll_ml_alloc_buffer(ml_module); while (NULL == src_buffer_desc) { opal_progress(); src_buffer_desc = mca_coll_ml_alloc_buffer(ml_module); } /* change 4 */ coll_op = mca_coll_ml_alloc_op_prog_single_frag_dag(ml_module, ml_module->coll_ml_allgather_functions[ML_SMALL_DATA_ALLGATHER], sbuf, rbuf, pack_len, 0 /* offset for first pack */); MCA_COLL_IBOFFLOAD_SET_ML_BUFFER_INFO(coll_op, src_buffer_desc->buffer_index, src_buffer_desc); topo_info = coll_op->coll_schedule->topo_info; /* task setup callback function */ coll_op->sequential_routine.seq_task_setup = mca_coll_ml_allgather_task_setup; if (!scontig) { coll_op->full_message.send_converter_bytes_packed = mca_coll_ml_convertor_prepare( sdtype, scount, NULL, &coll_op->full_message.dummy_convertor, MCA_COLL_ML_NET_STREAM_SEND); coll_op->full_message.dummy_conv_position = 0; mca_coll_ml_convertor_get_send_frag_size( ml_module, &frag_len, &coll_op->full_message); /* change 5 */ mca_coll_ml_convertor_prepare(sdtype, scount, sbuf, &coll_op->full_message.send_convertor, MCA_COLL_ML_NET_STREAM_SEND); mca_coll_ml_convertor_pack( (void *) ((uintptr_t) src_buffer_desc->data_addr + frag_len * (coll_op->coll_schedule->topo_info->hier_layout_info[0].offset + coll_op->coll_schedule->topo_info->hier_layout_info[0].level_one_index)), frag_len, &coll_op->full_message.send_convertor); } else { /* change 6 */ memcpy((void *)((uintptr_t)src_buffer_desc->data_addr + frag_len * (coll_op->coll_schedule->topo_info->hier_layout_info[0].offset + coll_op->coll_schedule->topo_info->hier_layout_info[0].level_one_index)), sbuf, frag_len); } if (!rcontig) { mca_coll_ml_convertor_prepare(rdtype, rcount * comm_size, rbuf, &coll_op->full_message.recv_convertor, MCA_COLL_ML_NET_STREAM_RECV); } coll_op->process_fn = mca_coll_ml_allgather_noncontiguous_unpack_data; /* hopefully this doesn't royaly screw things up idea behind this is the * whole ml-buffer is used to send and receive */ coll_op->variable_fn_params.sbuf = (void *) src_buffer_desc->data_addr; coll_op->variable_fn_params.rbuf = (void *) src_buffer_desc->data_addr; /* we can set the initial offset here */ coll_op->variable_fn_params.sbuf_offset = 0; coll_op->variable_fn_params.rbuf_offset = 0; coll_op->fragment_data.buffer_desc = src_buffer_desc; coll_op->fragment_data.fragment_size = frag_len; coll_op->fragment_data.message_descriptor->n_active = 1; coll_op->full_message.n_bytes_scheduled = frag_len; coll_op->full_message.fragment_launcher = mca_coll_ml_allgather_frag_progress; coll_op->full_message.pipeline_depth = pipeline_depth; coll_op->fragment_data.current_coll_op = ML_SMALL_DATA_ALLGATHER; /* remember this is different for frags !! Caused data corruption when * not properly set. Need to be sure you have consistent units. */ coll_op->variable_fn_params.count = frag_len; coll_op->variable_fn_params.dtype = MPI_BYTE; /* for fragmented data, we work in * units of bytes. This means that * all of our arithmetic is done * in terms of bytes */ coll_op->variable_fn_params.root = 0; coll_op->variable_fn_params.frag_size = frag_len; coll_op->variable_fn_params.buffer_size = frag_len; } else { /* change 7 */ ML_VERBOSE(10, ("ML_ALLGATHER_LARGE_DATA_KNOWN case.")); coll_op = mca_coll_ml_alloc_op_prog_single_frag_dag(ml_module, ml_module->coll_ml_allgather_functions[ML_LARGE_DATA_ALLGATHER], sbuf, rbuf, pack_len, 0 /* offset for first pack */); topo_info = coll_op->coll_schedule->topo_info; if (MCA_BCOL_BASE_NO_ML_BUFFER_FOR_LARGE_MSG & topo_info->all_bcols_mode) { MCA_COLL_IBOFFLOAD_SET_ML_BUFFER_INFO(coll_op, MCA_COLL_ML_NO_BUFFER, NULL); } else { src_buffer_desc = mca_coll_ml_alloc_buffer(ml_module); while (NULL == src_buffer_desc) { opal_progress(); src_buffer_desc = mca_coll_ml_alloc_buffer(ml_module); } MCA_COLL_IBOFFLOAD_SET_ML_BUFFER_INFO(coll_op, src_buffer_desc->buffer_index, src_buffer_desc); } /* not sure if I really need this here */ coll_op->sequential_routine.seq_task_setup = mca_coll_ml_allgather_task_setup; coll_op->process_fn = NULL; /* probably the most important piece */ coll_op->variable_fn_params.sbuf = sbuf; coll_op->variable_fn_params.rbuf = rbuf; coll_op->variable_fn_params.sbuf_offset = 0; coll_op->variable_fn_params.rbuf_offset = 0; coll_op->variable_fn_params.count = scount; coll_op->variable_fn_params.dtype = sdtype;/* for zero copy, we want the * native datatype and actual count */ coll_op->variable_fn_params.root = 0; /* you still need to copy in your own data into the rbuf */ /* don't need to do this if you have in place data */ if (!in_place) { memcpy((char *) rbuf + ompi_comm_rank(comm) * pack_len, sbuf, pack_len); } } coll_op->full_message.send_count = scount; coll_op->full_message.recv_count = rcount; coll_op->full_message.send_data_continguous = scontig; coll_op->full_message.recv_data_continguous = rcontig; ompi_datatype_get_extent(sdtype, &lb, &extent); coll_op->full_message.send_extent = (size_t) extent; ompi_datatype_get_extent(rdtype, &lb, &extent); coll_op->full_message.recv_extent = (size_t) extent; /* Fill in the function arguments */ coll_op->variable_fn_params.sequence_num = OPAL_THREAD_ADD32(&(ml_module->collective_sequence_num), 1); coll_op->variable_fn_params.hier_factor = comm_size; MCA_COLL_ML_SET_ORDER_INFO(coll_op, n_fragments); ret = mca_coll_ml_launch_sequential_collective (coll_op); if (OMPI_SUCCESS != ret) { ML_VERBOSE(10, ("Failed to launch")); return ret; } *req = &coll_op->full_message.super; return OMPI_SUCCESS; } int mca_coll_ml_allgather(void *sbuf, int scount, struct ompi_datatype_t *sdtype, void* rbuf, int rcount, struct ompi_datatype_t *rdtype, struct ompi_communicator_t *comm, mca_coll_base_module_t *module) { ompi_request_t *req; int ret; ML_VERBOSE(10, ("Starting blocking allgather")); ret = mca_coll_ml_allgather_start (sbuf, scount, sdtype, rbuf, rcount, rdtype, comm, module, &req); if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) { return ret; } ret = ompi_request_wait (&req, MPI_STATUS_IGNORE); ML_VERBOSE(10, ("Blocking allgather is complete")); return ret; } int mca_coll_ml_allgather_nb(void *sbuf, int scount, struct ompi_datatype_t *sdtype, void* rbuf, int rcount, struct ompi_datatype_t *rdtype, struct ompi_communicator_t *comm, ompi_request_t **req, mca_coll_base_module_t *module) { int ret; ML_VERBOSE(10, ("Starting non-blocking allgather")); ret = mca_coll_ml_allgather_start (sbuf, scount, sdtype, rbuf, rcount, rdtype, comm, module, req); if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) { return ret; } ML_VERBOSE(10, ("Non-blocking allgather started")); return ret; }