1 #include "colls_private.h"
2 /*****************************************************************************
4 * Function: alltoall_pair
9 send_buff: send input buffer
10 send_count: number of elements to send
11 send_type: data type of elements being sent
12 recv_buff: receive output buffer
13 recv_count: number of elements to received
14 recv_type: data type of elements being received
17 * Descrp: Function works when P is power of two. In each phase of P - 1
18 phases, nodes in pair communicate their data.
22 ****************************************************************************/
24 smpi_coll_tuned_alltoall_pair_one_barrier(void *send_buff, int send_count,
25 MPI_Datatype send_type,
26 void *recv_buff, int recv_count,
27 MPI_Datatype recv_type, MPI_Comm comm)
30 MPI_Aint send_chunk, recv_chunk;
32 int i, src, dst, rank, num_procs;
33 int tag = COLL_TAG_ALLTOALL;
35 char *send_ptr = (char *) send_buff;
36 char *recv_ptr = (char *) recv_buff;
38 rank = smpi_comm_rank(comm);
39 num_procs = smpi_comm_size(comm);
40 send_chunk = smpi_datatype_get_extent(send_type);
41 recv_chunk = smpi_datatype_get_extent(recv_type);
43 send_chunk *= send_count;
44 recv_chunk *= recv_count;
46 mpi_coll_barrier_fun(comm);
47 for (i = 0; i < num_procs; i++) {
49 smpi_mpi_sendrecv(send_ptr + dst * send_chunk, send_count, send_type, dst,
50 tag, recv_ptr + src * recv_chunk, recv_count, recv_type,