/* Algorithm: Recursive Doubling
 *
 * Restrictions: Intracommunicators Only
 *
 * We use the dissemination algorithm described in:
 * Debra Hensgen, Raphael Finkel, and Udi Manber, "Two Algorithms for
 * Barrier Synchronization," International Journal of Parallel
 * Programming, 17(1):1-17, 1988.
 *
 * It uses ceiling(lgp) steps. In step k, 0 <= k <= (ceiling(lgp)-1),
 * process i sends to process (i + 2^k) % p and receives from process
 * (i - 2^k + p) % p.
 */
int MPIR_Ibarrier_sched_intra_recursive_doubling(MPIR_Comm * comm_ptr, MPIR_Sched_t s)
{
    int mpi_errno = MPI_SUCCESS;
    int size, rank, src, dst, mask;

    MPIR_Assert(comm_ptr->comm_kind == MPIR_COMM_KIND__INTRACOMM);

    size = comm_ptr->local_size;
    rank = comm_ptr->rank;

    /* Trivial barriers return immediately */
    if (size == 1)
        goto fn_exit;

    mask = 0x1;
    while (mask < size) {
        dst = (rank + mask) % size;
        src = (rank - mask + size) % size;

        mpi_errno = MPIR_Sched_send(NULL, 0, MPI_BYTE, dst, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);

        mpi_errno = MPIR_Sched_recv(NULL, 0, MPI_BYTE, src, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);

        mpi_errno = MPIR_Sched_barrier(s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);

        mask <<= 1;
    }

  fn_exit:
    return mpi_errno;
  fn_fail:
    goto fn_exit;
}
int MPIR_Iallreduce_sched_inter_remote_reduce_local_bcast(const void *sendbuf, void *recvbuf,
                                                          int count, MPI_Datatype datatype,
                                                          MPI_Op op, MPIR_Comm * comm_ptr,
                                                          MPIR_Sched_t s)
{
    int mpi_errno = MPI_SUCCESS;
    int rank, root;
    MPIR_Comm *lcomm_ptr = NULL;

    MPIR_Assert(comm_ptr->comm_kind == MPIR_COMM_KIND__INTERCOMM);

    rank = comm_ptr->rank;

    /* first do a reduce from right group to rank 0 in left group,
     * then from left group to rank 0 in right group */
    if (comm_ptr->is_low_group) {
        /* reduce from right group to rank 0 */
        root = (rank == 0) ? MPI_ROOT : MPI_PROC_NULL;
        mpi_errno = MPIR_Ireduce_sched(sendbuf, recvbuf, count, datatype, op, root, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);

        /* no barrier, these reductions can be concurrent */

        /* reduce to rank 0 of right group */
        root = 0;
        mpi_errno = MPIR_Ireduce_sched(sendbuf, recvbuf, count, datatype, op, root, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);
    } else {
        /* reduce to rank 0 of left group */
        root = 0;
        mpi_errno = MPIR_Ireduce_sched(sendbuf, recvbuf, count, datatype, op, root, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);

        /* no barrier, these reductions can be concurrent */

        /* reduce from right group to rank 0 */
        root = (rank == 0) ? MPI_ROOT : MPI_PROC_NULL;
        mpi_errno = MPIR_Ireduce_sched(sendbuf, recvbuf, count, datatype, op, root, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);
    }

    /* don't bcast until the reductions have finished */
    mpi_errno = MPIR_Sched_barrier(s);
    if (mpi_errno)
        MPIR_ERR_POP(mpi_errno);

    /* Get the local intracommunicator */
    if (!comm_ptr->local_comm) {
        mpi_errno = MPII_Setup_intercomm_localcomm(comm_ptr);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);
    }
    lcomm_ptr = comm_ptr->local_comm;

    mpi_errno = MPIR_Ibcast_sched(recvbuf, count, datatype, 0, lcomm_ptr, s);
    if (mpi_errno)
        MPIR_ERR_POP(mpi_errno);

  fn_exit:
    return mpi_errno;
  fn_fail:
    goto fn_exit;
}
Esempio n. 3
0
int MPIR_Igather_sched_intra_binomial(const void *sendbuf, int sendcount, MPI_Datatype sendtype, void *recvbuf, int recvcount, MPI_Datatype recvtype, int root, MPIR_Comm *comm_ptr, MPIR_Sched_t s)
{
    int mpi_errno = MPI_SUCCESS;
    int comm_size, rank;
    int relative_rank, is_homogeneous;
    int mask, src, dst, relative_src;
    MPI_Aint recvtype_size, sendtype_size, curr_cnt=0, nbytes;
    int recvblks;
    int tmp_buf_size, missing;
    void *tmp_buf = NULL;
    int blocks[2];
    int displs[2];
    MPI_Aint struct_displs[2];
    MPI_Aint extent=0;
    int copy_offset = 0, copy_blks = 0;
    MPI_Datatype types[2], tmp_type;
    MPIR_SCHED_CHKPMEM_DECL(1);

    comm_size = comm_ptr->local_size;
    rank = comm_ptr->rank;

    if (((rank == root) && (recvcount == 0)) || ((rank != root) && (sendcount == 0)))
        goto fn_exit;

    is_homogeneous = TRUE;
#ifdef MPID_HAS_HETERO
    is_homogeneous = !comm_ptr->is_hetero;
#endif

    MPIR_Assert(comm_ptr->comm_kind == MPIR_COMM_KIND__INTRACOMM);

    /* Use binomial tree algorithm. */

    relative_rank = (rank >= root) ? rank - root : rank - root + comm_size;

    if (rank == root)
    {
        MPIR_Datatype_get_extent_macro(recvtype, extent);
        MPIR_Ensure_Aint_fits_in_pointer(MPIR_VOID_PTR_CAST_TO_MPI_AINT recvbuf+
                                         (extent*recvcount*comm_size));
    }

    if (is_homogeneous)
    {
        /* communicator is homogeneous. no need to pack buffer. */
        if (rank == root)
        {
            MPIR_Datatype_get_size_macro(recvtype, recvtype_size);
            nbytes = recvtype_size * recvcount;
        }
        else
        {
            MPIR_Datatype_get_size_macro(sendtype, sendtype_size);
            nbytes = sendtype_size * sendcount;
        }

        /* Find the number of missing nodes in my sub-tree compared to
         * a balanced tree */
        for (mask = 1; mask < comm_size; mask <<= 1);
        --mask;
        while (relative_rank & mask) mask >>= 1;
        missing = (relative_rank | mask) - comm_size + 1;
        if (missing < 0) missing = 0;
        tmp_buf_size = (mask - missing);

        /* If the message is smaller than the threshold, we will copy
         * our message in there too */
        if (nbytes < MPIR_CVAR_GATHER_VSMALL_MSG_SIZE) tmp_buf_size++;

        tmp_buf_size *= nbytes;

        /* For zero-ranked root, we don't need any temporary buffer */
        if ((rank == root) && (!root || (nbytes >= MPIR_CVAR_GATHER_VSMALL_MSG_SIZE)))
            tmp_buf_size = 0;

        if (tmp_buf_size) {
            MPIR_SCHED_CHKPMEM_MALLOC(tmp_buf, void *, tmp_buf_size, mpi_errno, "tmp_buf", MPL_MEM_BUFFER);
        }

        if (rank == root) {
            if (sendbuf != MPI_IN_PLACE) {
                mpi_errno = MPIR_Localcopy(sendbuf, sendcount, sendtype,
                                           ((char *) recvbuf + extent*recvcount*rank), recvcount, recvtype);
                if (mpi_errno) MPIR_ERR_POP(mpi_errno);
            }
        }
        else if (tmp_buf_size && (nbytes < MPIR_CVAR_GATHER_VSMALL_MSG_SIZE)) {
            /* copy from sendbuf into tmp_buf */
            mpi_errno = MPIR_Localcopy(sendbuf, sendcount, sendtype,
                                       tmp_buf, nbytes, MPI_BYTE);
            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
        }
        curr_cnt = nbytes;

        mask = 0x1;
        while (mask < comm_size) {
            if ((mask & relative_rank) == 0) {
                src = relative_rank | mask;
                if (src < comm_size) {
                    src = (src + root) % comm_size;

                    if (rank == root) {
                        recvblks = mask;
                        if ((2 * recvblks) > comm_size)
                            recvblks = comm_size - recvblks;

                        if ((rank + mask + recvblks == comm_size) ||
                            (((rank + mask) % comm_size) < ((rank + mask + recvblks) % comm_size)))
                        {
                            /* If the data contiguously fits into the
                             * receive buffer, place it directly. This
                             * should cover the case where the root is
                             * rank 0. */
                            char *rp = (char *)recvbuf + (((rank + mask) % comm_size)*recvcount*extent);
                            mpi_errno = MPIR_Sched_recv(rp, (recvblks * recvcount), recvtype, src, comm_ptr, s);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                            mpi_errno = MPIR_Sched_barrier(s);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                        }
                        else if (nbytes < MPIR_CVAR_GATHER_VSMALL_MSG_SIZE) {
                            mpi_errno = MPIR_Sched_recv(tmp_buf, (recvblks * nbytes), MPI_BYTE, src, comm_ptr, s);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                            mpi_errno = MPIR_Sched_barrier(s);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                            copy_offset = rank + mask;
                            copy_blks = recvblks;
                        }
                        else {
                            blocks[0] = recvcount * (comm_size - root - mask);
                            displs[0] = recvcount * (root + mask);
                            blocks[1] = (recvcount * recvblks) - blocks[0];
                            displs[1] = 0;

                            mpi_errno = MPIR_Type_indexed_impl(2, blocks, displs, recvtype, &tmp_type);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                            mpi_errno = MPIR_Type_commit_impl(&tmp_type);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);

                            mpi_errno = MPIR_Sched_recv(recvbuf, 1, tmp_type, src, comm_ptr, s);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                            mpi_errno = MPIR_Sched_barrier(s);
                            if (mpi_errno) MPIR_ERR_POP(mpi_errno);

                            /* this "premature" free is safe b/c the sched holds an actual ref to keep it alive */
                            MPIR_Type_free_impl(&tmp_type);
                        }
                    }
                    else { /* Intermediate nodes store in temporary buffer */
                        MPI_Aint offset;

                        /* Estimate the amount of data that is going to come in */
                        recvblks = mask;
                        relative_src = ((src - root) < 0) ? (src - root + comm_size) : (src - root);
                        if (relative_src + mask > comm_size)
                            recvblks -= (relative_src + mask - comm_size);

                        if (nbytes < MPIR_CVAR_GATHER_VSMALL_MSG_SIZE)
                            offset = mask * nbytes;
                        else
                            offset = (mask - 1) * nbytes;
                        mpi_errno = MPIR_Sched_recv(((char *)tmp_buf + offset), (recvblks * nbytes),
                                                    MPI_BYTE, src, comm_ptr, s);
                        if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                        mpi_errno = MPIR_Sched_barrier(s);
                        if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                        curr_cnt += (recvblks * nbytes);
                    }
                }
            }
            else {
                dst = relative_rank ^ mask;
                dst = (dst + root) % comm_size;

                if (!tmp_buf_size) {
                    /* leaf nodes send directly from sendbuf */
                    mpi_errno = MPIR_Sched_send(sendbuf, sendcount, sendtype, dst, comm_ptr, s);
                    if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                    mpi_errno = MPIR_Sched_barrier(s);
                    if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                }
                else if (nbytes < MPIR_CVAR_GATHER_VSMALL_MSG_SIZE) {
                    mpi_errno = MPIR_Sched_send(tmp_buf, curr_cnt, MPI_BYTE, dst, comm_ptr, s);
                    if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                    mpi_errno = MPIR_Sched_barrier(s);
                    if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                }
                else {
                    blocks[0] = sendcount;
                    struct_displs[0] = MPIR_VOID_PTR_CAST_TO_MPI_AINT sendbuf;
                    types[0] = sendtype;
		    /* check for overflow.  work around int limits if needed*/
		    if (curr_cnt - nbytes != (int)(curr_cnt-nbytes)) {
			blocks[1] = 1;
			MPIR_Type_contiguous_x_impl(curr_cnt - nbytes,
				MPI_BYTE, &(types[1]));
		    } else {
			MPIR_Assign_trunc(blocks[1], curr_cnt - nbytes, int);
			types[1] = MPI_BYTE;
		    }
                    struct_displs[1] = MPIR_VOID_PTR_CAST_TO_MPI_AINT tmp_buf;

                    mpi_errno = MPIR_Type_create_struct_impl(2, blocks, struct_displs, types, &tmp_type);
                    if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                    mpi_errno = MPIR_Type_commit_impl(&tmp_type);
                    if (mpi_errno) MPIR_ERR_POP(mpi_errno);

                    mpi_errno = MPIR_Sched_send(MPI_BOTTOM, 1, tmp_type, dst, comm_ptr, s);
                    if (mpi_errno) MPIR_ERR_POP(mpi_errno);
                    MPIR_SCHED_BARRIER(s);

                    /* this "premature" free is safe b/c the sched holds an actual ref to keep it alive */
                    MPIR_Type_free_impl(&tmp_type);
                }

                break;
            }
            mask <<= 1;
        }

        if ((rank == root) && root && (nbytes < MPIR_CVAR_GATHER_VSMALL_MSG_SIZE) && copy_blks) {
            /* reorder and copy from tmp_buf into recvbuf */
            /* FIXME why are there two copies here? */
            mpi_errno = MPIR_Sched_copy(tmp_buf, nbytes * (comm_size - copy_offset), MPI_BYTE,
                                       ((char *)recvbuf + extent * recvcount * copy_offset),
                                       recvcount * (comm_size - copy_offset), recvtype, s);
            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
            mpi_errno = MPIR_Sched_copy((char *)tmp_buf + nbytes * (comm_size - copy_offset),
                                        nbytes * (copy_blks - comm_size + copy_offset), MPI_BYTE,
                                        recvbuf, recvcount * (copy_blks - comm_size + copy_offset),
                                        recvtype, s);
            if (mpi_errno) MPIR_ERR_POP(mpi_errno);
        }
    }
#ifdef MPID_HAS_HETERO
    else {