Ejemplo n.º 1
0
/* try to get a small message out on to the wire quickly */
static inline int mca_pml_ob1_send_inline (const void *buf, size_t count,
                                           ompi_datatype_t * datatype,
                                           int dst, int tag, int16_t seqn,
                                           ompi_proc_t *dst_proc, mca_bml_base_endpoint_t* endpoint,
                                           ompi_communicator_t * comm)
{
    mca_pml_ob1_match_hdr_t match;
    mca_bml_base_btl_t *bml_btl;
    opal_convertor_t convertor;
    size_t size;
    int rc;

    bml_btl = mca_bml_base_btl_array_get_next(&endpoint->btl_eager);
    if( NULL == bml_btl->btl->btl_sendi)
        return OMPI_ERR_NOT_AVAILABLE;

    ompi_datatype_type_size (datatype, &size);
    if ((size * count) > 256) {  /* some random number */
        return OMPI_ERR_NOT_AVAILABLE;
    }

    if (count > 0) {
        /* initialize just enough of the convertor to avoid a SEGV in opal_convertor_cleanup */
        OBJ_CONSTRUCT(&convertor, opal_convertor_t);

        /* We will create a convertor specialized for the        */
        /* remote architecture and prepared with the datatype.   */
        opal_convertor_copy_and_prepare_for_send (dst_proc->super.proc_convertor,
                                                  (const struct opal_datatype_t *) datatype,
                                                  count, buf, 0, &convertor);
        opal_convertor_get_packed_size (&convertor, &size);
    } else {
        size = 0;
    }

    mca_pml_ob1_match_hdr_prepare (&match, MCA_PML_OB1_HDR_TYPE_MATCH, 0,
                                   comm->c_contextid, comm->c_my_rank,
                                   tag, seqn);

    ob1_hdr_hton(&match, MCA_PML_OB1_HDR_TYPE_MATCH, dst_proc);

    /* try to send immediately */
    rc = mca_bml_base_sendi (bml_btl, &convertor, &match, OMPI_PML_OB1_MATCH_HDR_LEN,
                             size, MCA_BTL_NO_ORDER, MCA_BTL_DES_FLAGS_PRIORITY | MCA_BTL_DES_FLAGS_BTL_OWNERSHIP,
                             MCA_PML_OB1_HDR_TYPE_MATCH, NULL);
    if (count > 0) {
        opal_convertor_cleanup (&convertor);
    }

    if (OPAL_UNLIKELY(OMPI_SUCCESS != rc)) {
	return rc;
    }

    return (int) size;
}
Ejemplo n.º 2
0
static mca_pml_yalla_convertor_t *mca_pml_yalla_get_send_convertor(void *buf, size_t count,
                                                                   ompi_datatype_t *datatype)
{
    mca_pml_yalla_convertor_t *convertor = PML_YALLA_FREELIST_GET(&ompi_pml_yalla.convs);

    convertor->datatype = datatype;
    OBJ_RETAIN(datatype);
    opal_convertor_copy_and_prepare_for_send(ompi_proc_local_proc->proc_convertor,
                                             &datatype->super, count, buf, 0,
                                             &convertor->convertor);
    return convertor;
}
Ejemplo n.º 3
0
static inline int create_iov_list(const void *addr, int count, ompi_datatype_t *datatype,
                                  ucx_iovec_t **ucx_iov, uint32_t *ucx_iov_count) {
    int ret = OMPI_SUCCESS;
    size_t size;
    bool done = false;
    opal_convertor_t convertor;
    uint32_t iov_count, iov_idx;
    struct iovec iov[OSC_UCX_IOVEC_MAX];
    uint32_t ucx_iov_idx;

    OBJ_CONSTRUCT(&convertor, opal_convertor_t);
    ret = opal_convertor_copy_and_prepare_for_send(ompi_mpi_local_convertor,
                                                   &datatype->super, count,
                                                   addr, 0, &convertor);
    if (ret != OMPI_SUCCESS) {
        return ret;
    }

    (*ucx_iov_count) = 0;
    ucx_iov_idx = 0;

    do {
        iov_count = OSC_UCX_IOVEC_MAX;
        iov_idx = 0;

        done = opal_convertor_raw(&convertor, iov, &iov_count, &size);

        (*ucx_iov_count) += iov_count;
        (*ucx_iov) = (ucx_iovec_t *)realloc((*ucx_iov), (*ucx_iov_count) * sizeof(ucx_iovec_t));
        if (*ucx_iov == NULL) {
            return OMPI_ERR_TEMP_OUT_OF_RESOURCE;
        }

        while (iov_idx != iov_count) {
            (*ucx_iov)[ucx_iov_idx].addr = iov[iov_idx].iov_base;
            (*ucx_iov)[ucx_iov_idx].len = iov[iov_idx].iov_len;
            ucx_iov_idx++;
            iov_idx++;
        }

        assert((*ucx_iov_count) == ucx_iov_idx);

    } while (!done);

    opal_convertor_cleanup(&convertor);
    OBJ_DESTRUCT(&convertor);

    return ret;
}
/*
 * opal_datatype_sndrcv
 *
 * Function: - copy MPI message from buffer into another
 *           - send/recv done if cannot optimize
 * Accepts:  - send buffer
 *           - send count
 *           - send datatype
 *           - receive buffer
 *           - receive count
 *           - receive datatype
 *           - tag
 *           - communicator
 * Returns:  - MPI_SUCCESS or error code
 */
int32_t ompi_datatype_sndrcv( void *sbuf, int32_t scount, const ompi_datatype_t* sdtype,
                              void *rbuf, int32_t rcount, const ompi_datatype_t* rdtype)
{
    opal_convertor_t send_convertor, recv_convertor;
    struct iovec iov;
    int length, completed;
    uint32_t iov_count;
    size_t max_data;

    /* First check if we really have something to do */
    if (0 == rcount || 0 == rdtype->super.size) {
        return ((0 == scount || 0 == sdtype->super.size) ? MPI_SUCCESS : MPI_ERR_TRUNCATE);
    }

    /* If same datatypes used, just copy. */
    if (sdtype == rdtype) {
        int32_t count = ( scount < rcount ? scount : rcount );
        opal_datatype_copy_content_same_ddt(&(rdtype->super), count, (char*)rbuf, (char*)sbuf);
        return ((scount > rcount) ? MPI_ERR_TRUNCATE : MPI_SUCCESS);
    }

    /* If receive packed. */
    if (rdtype->id == OMPI_DATATYPE_MPI_PACKED) {
        OBJ_CONSTRUCT( &send_convertor, opal_convertor_t );
        opal_convertor_copy_and_prepare_for_send( ompi_mpi_local_convertor,
                                                  &(sdtype->super), scount, sbuf, 0,
                                                  &send_convertor );

        iov_count = 1;
        iov.iov_base = (IOVBASE_TYPE*)rbuf;
        iov.iov_len = scount * sdtype->super.size;
        if( (int32_t)iov.iov_len > rcount ) iov.iov_len = rcount;

        opal_convertor_pack( &send_convertor, &iov, &iov_count, &max_data );
        OBJ_DESTRUCT( &send_convertor );
        return ((max_data < (size_t)rcount) ? MPI_ERR_TRUNCATE : MPI_SUCCESS);
    }

    /* If send packed. */
    if (sdtype->id == OMPI_DATATYPE_MPI_PACKED) {
        OBJ_CONSTRUCT( &recv_convertor, opal_convertor_t );
        opal_convertor_copy_and_prepare_for_recv( ompi_mpi_local_convertor,
                                                  &(rdtype->super), rcount, rbuf, 0,
                                                  &recv_convertor );

        iov_count = 1;
        iov.iov_base = (IOVBASE_TYPE*)sbuf;
        iov.iov_len = rcount * rdtype->super.size;
        if( (int32_t)iov.iov_len > scount ) iov.iov_len = scount;

        opal_convertor_unpack( &recv_convertor, &iov, &iov_count, &max_data );
        OBJ_DESTRUCT( &recv_convertor );
        return (((size_t)scount > max_data) ? MPI_ERR_TRUNCATE : MPI_SUCCESS);
    }

    iov.iov_len = length = 64 * 1024;
    iov.iov_base = (IOVBASE_TYPE*)malloc( length * sizeof(char) );

    OBJ_CONSTRUCT( &send_convertor, opal_convertor_t );
    opal_convertor_copy_and_prepare_for_send( ompi_mpi_local_convertor,
                                              &(sdtype->super), scount, sbuf, 0,
                                              &send_convertor );
    OBJ_CONSTRUCT( &recv_convertor, opal_convertor_t );
    opal_convertor_copy_and_prepare_for_recv( ompi_mpi_local_convertor,
                                              &(rdtype->super), rcount, rbuf, 0,
                                              &recv_convertor );

    completed = 0;
    while( !completed ) {
        iov.iov_len = length;
        iov_count = 1;
        max_data = length;
        completed |= opal_convertor_pack( &send_convertor, &iov, &iov_count, &max_data );
        completed |= opal_convertor_unpack( &recv_convertor, &iov, &iov_count, &max_data );
    }
    free( iov.iov_base );
    OBJ_DESTRUCT( &send_convertor );
    OBJ_DESTRUCT( &recv_convertor );

    return ( (scount * sdtype->super.size) <= (rcount * rdtype->super.size) ? MPI_SUCCESS : MPI_ERR_TRUNCATE );
}
Ejemplo n.º 5
0
/* try to get a small message out on to the wire quickly */
static inline int mca_pml_ob1_send_inline (void *buf, size_t count,
                                           ompi_datatype_t * datatype,
                                           int dst, int tag, int16_t seqn,
                                           ompi_proc_t *dst_proc, mca_bml_base_endpoint_t* endpoint,
                                           ompi_communicator_t * comm)
{
    mca_btl_base_descriptor_t *des = NULL;
    mca_pml_ob1_match_hdr_t match;
    mca_bml_base_btl_t *bml_btl;
    OPAL_PTRDIFF_TYPE lb, extent;
    opal_convertor_t convertor;
    size_t size = 0;
    int rc;

    bml_btl = mca_bml_base_btl_array_get_next(&endpoint->btl_eager);

    ompi_datatype_get_extent (datatype, &lb, &extent);

    if (OPAL_UNLIKELY((extent * count) > 256 || !bml_btl->btl->btl_sendi)) {
        return OMPI_ERR_NOT_AVAILABLE;
    }

    if (count > 0) {
        /* initialize just enough of the convertor to avoid a SEGV in opal_convertor_cleanup */
        OBJ_CONSTRUCT(&convertor, opal_convertor_t);

        /* We will create a convertor specialized for the        */
        /* remote architecture and prepared with the datatype.   */
        opal_convertor_copy_and_prepare_for_send (dst_proc->proc_convertor,
                                                  (const struct opal_datatype_t *) datatype,
						  count, buf, 0, &convertor);
        opal_convertor_get_packed_size (&convertor, &size);
    }

    match.hdr_common.hdr_flags = 0;
    match.hdr_common.hdr_type = MCA_PML_OB1_HDR_TYPE_MATCH;
    match.hdr_ctx = comm->c_contextid;
    match.hdr_src = comm->c_my_rank;
    match.hdr_tag = tag;
    match.hdr_seq = seqn;

    ob1_hdr_hton(&match, MCA_PML_OB1_HDR_TYPE_MATCH, dst_proc);

    /* try to send immediately */
    rc = mca_bml_base_sendi (bml_btl, &convertor, &match, OMPI_PML_OB1_MATCH_HDR_LEN,
                             size, MCA_BTL_NO_ORDER, MCA_BTL_DES_FLAGS_PRIORITY | MCA_BTL_DES_FLAGS_BTL_OWNERSHIP,
                             MCA_PML_OB1_HDR_TYPE_MATCH, &des);
    if (count > 0) {
        opal_convertor_cleanup (&convertor);
    }

    if (OPAL_UNLIKELY(OMPI_SUCCESS != rc)) {
        if (des) {
            mca_bml_base_free (bml_btl, des);
        }

	return rc;
    }

    return (int) size;
}
Ejemplo n.º 6
0
static inline int ompi_osc_rdma_gacc_master (ompi_osc_rdma_sync_t *sync, const void *source_buffer, int source_count,
                                             ompi_datatype_t *source_datatype, void *result_buffer, int result_count,
                                             ompi_datatype_t *result_datatype, ompi_osc_rdma_peer_t *peer, uint64_t target_address,
                                             mca_btl_base_registration_handle_t *target_handle, int target_count,
                                             ompi_datatype_t *target_datatype, ompi_op_t *op, ompi_osc_rdma_request_t *request)
{
    ompi_osc_rdma_module_t *module = sync->module;
    struct iovec source_iovec[OMPI_OSC_RDMA_DECODE_MAX], target_iovec[OMPI_OSC_RDMA_DECODE_MAX];
    const size_t acc_limit = (mca_osc_rdma_component.buffer_size >> 3);
    uint32_t source_primitive_count, target_primitive_count;
    opal_convertor_t source_convertor, target_convertor;
    uint32_t source_iov_count, target_iov_count;
    uint32_t source_iov_index, target_iov_index;
    ompi_datatype_t *source_primitive, *target_primitive;
    /* needed for opal_convertor_raw but not used */
    size_t source_size, target_size;
    ompi_osc_rdma_request_t *subreq;
    size_t result_position;
    ptrdiff_t lb, extent;
    int ret, acc_len;
    bool done;

    (void) ompi_datatype_get_extent (target_datatype, &lb, &extent);
    target_address += lb;

    /* fast path for accumulate on built-in types */
    if (OPAL_LIKELY((!source_count || ompi_datatype_is_predefined (source_datatype)) &&
                    ompi_datatype_is_predefined (target_datatype) &&
                    (!result_count || ompi_datatype_is_predefined (result_datatype)) &&
                    (target_datatype->super.size * target_count <= acc_limit))) {
        if (NULL == request) {
            OMPI_OSC_RDMA_REQUEST_ALLOC(module, peer, request);
            request->internal = true;
            request->type = result_datatype ? OMPI_OSC_RDMA_TYPE_GET_ACC : OMPI_OSC_RDMA_TYPE_ACC;
        }

        if (source_datatype) {
            (void) ompi_datatype_get_extent (source_datatype, &lb, &extent);
            source_buffer = (void *)((intptr_t) source_buffer + lb);
        }

        if (result_datatype) {
            (void) ompi_datatype_get_extent (result_datatype, &lb, &extent);
            result_buffer = (void *)((intptr_t) result_buffer + lb);
        }

        ret = ompi_osc_rdma_gacc_contig (sync, source_buffer, source_count, source_datatype, result_buffer,
                                         result_count, result_datatype, peer, target_address,
                                         target_handle, target_count, target_datatype, op,
                                         request);
        if (OPAL_LIKELY(OMPI_SUCCESS == ret)) {
            return OMPI_SUCCESS;
        }

        if (source_datatype) {
            /* the convertors will handle the lb */
            (void) ompi_datatype_get_extent (source_datatype, &lb, &extent);
            source_buffer = (void *)((intptr_t) source_buffer - lb);
        }

        if (result_datatype) {
            (void) ompi_datatype_get_extent (result_datatype, &lb, &extent);
            result_buffer = (void *)((intptr_t) result_buffer - lb);
        }
    }

    /* the convertor will handle lb from here */
    (void) ompi_datatype_get_extent (target_datatype, &lb, &extent);
    target_address -= lb;

    /* get the primitive datatype info */
    ret = ompi_osc_base_get_primitive_type_info (target_datatype, &target_primitive, &target_primitive_count);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) {
        /* target datatype is not made up of a single basic datatype */
        return ret;
    }

    if (source_datatype) {
        ret = ompi_osc_base_get_primitive_type_info (source_datatype, &source_primitive, &source_primitive_count);
        if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) {
            /* target datatype is not made up of a single basic datatype */
            return ret;
        }

        if (OPAL_UNLIKELY(source_primitive != target_primitive)) {
            return MPI_ERR_TYPE;
        }
    }

    /* prepare convertors for the source and target. these convertors will be used to determine the
     * contiguous segments within the source and target. */
    /* the source may be NULL if using MPI_OP_NO_OP with MPI_Get_accumulate */
    if (source_datatype) {
        OBJ_CONSTRUCT(&source_convertor, opal_convertor_t);
        ret = opal_convertor_copy_and_prepare_for_send (ompi_mpi_local_convertor, &source_datatype->super, source_count, source_buffer,
                                                       0, &source_convertor);
        if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) {
            return ret;
        }
    }

    /* target_datatype can never be NULL */
    OBJ_CONSTRUCT(&target_convertor, opal_convertor_t);
    ret = opal_convertor_copy_and_prepare_for_send (ompi_mpi_local_convertor, &target_datatype->super, target_count,
                                                    (void *) (intptr_t) target_address, 0, &target_convertor);
    if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) {
        return ret;
    }

    if (request) {
        /* keep the request from completing until all the transfers have started */
        request->outstanding_requests = 1;
    }

    target_iov_index = 0;
    target_iov_count = 0;
    result_position = 0;

    do {
        /* decode segments of the source data */
        source_iov_count = OMPI_OSC_RDMA_DECODE_MAX;
        source_iov_index = 0;
        /* opal_convertor_raw returns done when it has reached the end of the data */
        if (!source_datatype) {
            done = true;
            source_iovec[0].iov_len = (size_t) -1;
            source_iovec[0].iov_base = NULL;
            source_iov_count = 1;
        } else {
            done = opal_convertor_raw (&source_convertor, source_iovec, &source_iov_count, &source_size);
        }

        /* loop on the target segments until we have exhaused the decoded source data */
        while (source_iov_index != source_iov_count) {
            if (target_iov_index == target_iov_count) {
                /* decode segments of the target buffer */
                target_iov_count = OMPI_OSC_RDMA_DECODE_MAX;
                target_iov_index = 0;
                (void) opal_convertor_raw (&target_convertor, target_iovec, &target_iov_count, &target_size);
            }

            /* we already checked that the target was large enough. this should be impossible */
            assert (0 != target_iov_count);

            /* determine how much to put in this operation */
            acc_len = min(target_iovec[target_iov_index].iov_len, source_iovec[source_iov_index].iov_len);
            acc_len = min((size_t) acc_len, acc_limit);

            /* execute the get */
            OMPI_OSC_RDMA_REQUEST_ALLOC(module, peer, subreq);
            subreq->internal = true;
            subreq->parent_request = request;
            if (request) {
                (void) OPAL_THREAD_ADD32 (&request->outstanding_requests, 1);
            }

            if (result_datatype) {
                /* prepare a convertor for this part of the result */
                opal_convertor_copy_and_prepare_for_recv (ompi_mpi_local_convertor, &result_datatype->super, result_count,
                                                          result_buffer, 0, &subreq->convertor);
                opal_convertor_set_position (&subreq->convertor, &result_position);
                subreq->type = OMPI_OSC_RDMA_TYPE_GET_ACC;
            } else {
                subreq->type = OMPI_OSC_RDMA_TYPE_ACC;
            }

            OPAL_OUTPUT_VERBOSE((60, ompi_osc_base_framework.framework_output,
                                 "target index = %d, target = {%p, %lu}, source_index = %d, source = {%p, %lu}, result = %p, result position = %lu, "
                                 "acc_len = %d, count = %lu",
                                 target_iov_index, target_iovec[target_iov_index].iov_base, (unsigned long) target_iovec[target_iov_index].iov_len,
                                 source_iov_index, source_iovec[source_iov_index].iov_base, (unsigned long) source_iovec[source_iov_index].iov_len,
                                 result_buffer, (unsigned long) result_position, acc_len, (unsigned long)(acc_len / target_primitive->super.size)));


            ret = ompi_osc_rdma_gacc_contig (sync, source_iovec[source_iov_index].iov_base, acc_len / target_primitive->super.size,
                                             target_primitive, NULL, 0, NULL, peer, (uint64_t) (intptr_t) target_iovec[target_iov_index].iov_base,
                                             target_handle, acc_len / target_primitive->super.size, target_primitive, op, subreq);
            if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) {
                if (OPAL_UNLIKELY(OMPI_ERR_OUT_OF_RESOURCE != ret)) {
                    /* something bad happened. need to figure out how to handle these errors */
                    return ret;
                }

                /* progress and try again */
                ompi_osc_rdma_progress (module);
                continue;
            }

            /* adjust io vectors */
            target_iovec[target_iov_index].iov_len -= acc_len;
            source_iovec[source_iov_index].iov_len -= acc_len;
            target_iovec[target_iov_index].iov_base = (void *)((intptr_t) target_iovec[target_iov_index].iov_base + acc_len);
            source_iovec[source_iov_index].iov_base = (void *)((intptr_t) source_iovec[source_iov_index].iov_base + acc_len);
            result_position += acc_len;

            source_iov_index += !source_datatype || (0 == source_iovec[source_iov_index].iov_len);
            target_iov_index += (0 == target_iovec[target_iov_index].iov_len);
        }
    } while (!done);

    if (request) {
        /* release our reference so the request can complete */
        (void) OPAL_THREAD_ADD32 (&request->outstanding_requests, -1);
    }

    if (source_datatype) {
        opal_convertor_cleanup (&source_convertor);
        OBJ_DESTRUCT(&source_convertor);
    }

    opal_convertor_cleanup (&target_convertor);
    OBJ_DESTRUCT(&target_convertor);

    return OMPI_SUCCESS;
}
Ejemplo n.º 7
0
/**
 * Shared memory broadcast.
 *
 * For the root, the general algorithm is to wait for a set of
 * segments to become available.  Once it is, the root claims the set
 * by writing the current operation number and the number of processes
 * using the set to the flag.  The root then loops over the set of
 * segments; for each segment, it copies a fragment of the user's
 * buffer into the shared data segment and then writes the data size
 * into its childrens' control buffers.  The process is repeated until
 * all fragments have been written.
 *
 * For non-roots, for each set of buffers, they wait until the current
 * operation number appears in the in-use flag (i.e., written by the
 * root).  Then for each segment, they wait for a nonzero to appear
 * into their control buffers.  If they have children, they copy the
 * data from their parent's shared data segment into their shared data
 * segment, and write the data size into each of their childrens'
 * control buffers.  They then copy the data from their shared [local]
 * data segment into the user's output buffer.  The process is
 * repeated until all fragments have been received.  If they do not
 * have children, they copy the data directly from the parent's shared
 * data segment into the user's output buffer.
 */
int mca_coll_sm_bcast_intra(void *buff, int count,
                            struct ompi_datatype_t *datatype, int root,
                            struct ompi_communicator_t *comm,
                            mca_coll_base_module_t *module)
{
    struct iovec iov;
    mca_coll_sm_module_t *sm_module = (mca_coll_sm_module_t*) module;
    mca_coll_sm_comm_t *data;
    int i, ret, rank, size, num_children, src_rank;
    int flag_num, segment_num, max_segment_num;
    int parent_rank;
    size_t total_size, max_data, bytes;
    mca_coll_sm_in_use_flag_t *flag;
    opal_convertor_t convertor;
    mca_coll_sm_tree_node_t *me, *parent, **children;
    mca_coll_sm_data_index_t *index;

    /* Lazily enable the module the first time we invoke a collective
       on it */
    if (!sm_module->enabled) {
        if (OMPI_SUCCESS != (ret = ompi_coll_sm_lazy_enable(module, comm))) {
            return ret;
        }
    }
    data = sm_module->sm_comm_data;

    /* Setup some identities */

    rank = ompi_comm_rank(comm);
    size = ompi_comm_size(comm);

    OBJ_CONSTRUCT(&convertor, opal_convertor_t);
    iov.iov_len = mca_coll_sm_component.sm_fragment_size;
    bytes = 0;

    me = &data->mcb_tree[(rank + size - root) % size];
    parent = me->mcstn_parent;
    children = me->mcstn_children;
    num_children = me->mcstn_num_children;

    /* Only have one top-level decision as to whether I'm the root or
       not.  Do this at the slight expense of repeating a little logic
       -- but it's better than a conditional branch in every loop
       iteration. */

    /*********************************************************************
     * Root
     *********************************************************************/

    if (root == rank) {

        /* The root needs a send convertor to pack from the user's
           buffer to shared memory */

        if (OMPI_SUCCESS !=
            (ret =
             opal_convertor_copy_and_prepare_for_send(ompi_mpi_local_convertor,
                                                      &(datatype->super),
                                                      count,
                                                      buff,
                                                      0,
                                                      &convertor))) {
            return ret;
        }
        opal_convertor_get_packed_size(&convertor, &total_size);

        /* Main loop over sending fragments */

        do {
            flag_num = (data->mcb_operation_count++ %
                        mca_coll_sm_component.sm_comm_num_in_use_flags);

            FLAG_SETUP(flag_num, flag, data);
            FLAG_WAIT_FOR_IDLE(flag, bcast_root_label);
            FLAG_RETAIN(flag, size - 1, data->mcb_operation_count - 1);

            /* Loop over all the segments in this set */

            segment_num =
                flag_num * mca_coll_sm_component.sm_segs_per_inuse_flag;
            max_segment_num =
                (flag_num + 1) * mca_coll_sm_component.sm_segs_per_inuse_flag;
            do {
                index = &(data->mcb_data_index[segment_num]);

                /* Copy the fragment from the user buffer to my fragment
                   in the current segment */
                max_data = mca_coll_sm_component.sm_fragment_size;
                COPY_FRAGMENT_IN(convertor, index, rank, iov, max_data);
                bytes += max_data;

                /* Wait for the write to absolutely complete */
                opal_atomic_wmb();

                /* Tell my children that this fragment is ready */
                PARENT_NOTIFY_CHILDREN(children, num_children, index,
                                       max_data);

                ++segment_num;
            } while (bytes < total_size && segment_num < max_segment_num);
        } while (bytes < total_size);
    }

    /*********************************************************************
     * Non-root
     *********************************************************************/

    else {

        /* Non-root processes need a receive convertor to unpack from
           shared mmory to the user's buffer */

        if (OMPI_SUCCESS !=
            (ret =
             opal_convertor_copy_and_prepare_for_recv(ompi_mpi_local_convertor,
                                                      &(datatype->super),
                                                      count,
                                                      buff,
                                                      0,
                                                      &convertor))) {
            return ret;
        }
        opal_convertor_get_packed_size(&convertor, &total_size);

        /* Loop over receiving (and possibly re-sending) the
           fragments */

        do {
            flag_num = (data->mcb_operation_count %
                        mca_coll_sm_component.sm_comm_num_in_use_flags);

            /* Wait for the root to mark this set of segments as
               ours */
            FLAG_SETUP(flag_num, flag, data);
            FLAG_WAIT_FOR_OP(flag, data->mcb_operation_count, bcast_nonroot_label1);
            ++data->mcb_operation_count;

            /* Loop over all the segments in this set */

            segment_num =
                flag_num * mca_coll_sm_component.sm_segs_per_inuse_flag;
            max_segment_num =
                (flag_num + 1) * mca_coll_sm_component.sm_segs_per_inuse_flag;
            do {

                /* Pre-calculate some values */
                parent_rank = (parent->mcstn_id + root) % size;
                index = &(data->mcb_data_index[segment_num]);

                /* Wait for my parent to tell me that the segment is ready */
                CHILD_WAIT_FOR_NOTIFY(rank, index, max_data, bcast_nonroot_label2);

                /* If I have children, send the data to them */
                if (num_children > 0) {
                    /* Copy the fragment from the parent's portion in
                       the segment to my portion in the segment. */
                    COPY_FRAGMENT_BETWEEN(parent_rank, rank, index, max_data);

                    /* Wait for the write to absolutely complete */
                    opal_atomic_wmb();

                    /* Tell my children that this fragment is ready */
                    PARENT_NOTIFY_CHILDREN(children, num_children, index,
                                           max_data);

                    /* Set the "copy from buffer" to be my local
                       segment buffer so that we don't potentially
                       incur a non-local memory copy from the parent's
                       fan out data segment [again] when copying to
                       the user's buffer */
                    src_rank = rank;
                }

                /* If I don't have any children, set the "copy from
                   buffer" to be my parent's fan out segment to copy
                   directly from my parent */

                else {
                    src_rank = parent_rank;
                }

                /* Copy to my output buffer */
                COPY_FRAGMENT_OUT(convertor, src_rank, index, iov, max_data);

                bytes += max_data;
                ++segment_num;
            } while (bytes < total_size && segment_num < max_segment_num);

            /* Wait for all copy-out writes to complete before I say
               I'm done with the segments */
            opal_atomic_wmb();

            /* We're finished with this set of segments */
            FLAG_RELEASE(flag);
        } while (bytes < total_size);
    }

    /* Kill the convertor */

    OBJ_DESTRUCT(&convertor);

    /* All done */

    return OMPI_SUCCESS;
}