+++ /dev/null
-#include "colls.h"
-
-int
-smpi_coll_tuned_allgather_RDB(void *sbuf, int send_count,
- MPI_Datatype send_type,
- void *rbuf, int recv_count,
- MPI_Datatype recv_type,
- MPI_Comm comm)
-{
- // MPI variables
- MPI_Status status;
- MPI_Aint send_chunk, recv_chunk;
-
- // local int variables
- int i, j, k, dst, rank, num_procs, send_offset, recv_offset, tree_root;
- int dst_tree_root, rank_tree_root, last_recv_count, num_procs_completed;
- int offset, tmp_mask;
- int tag = 1;
- int mask = 1;
- int success = 0;
- int curr_count = recv_count;
-
- // local string variables
- char *send_ptr = (char *) sbuf;
- char *recv_ptr = (char *) rbuf;
-
- // get size of the communicator, followed by rank
- MPI_Comm_size(comm, &num_procs);
- MPI_Comm_rank(comm, &rank);
-
- // get size of single element's type for send buffer and recv buffer
- MPI_Type_extent(send_type, &send_chunk);
- MPI_Type_extent(recv_type, &recv_chunk);
-
- // multiply size of each element by number of elements to send or recv
- send_chunk *= send_count;
- recv_chunk *= recv_count;
-
- // perform a local copy
- MPI_Sendrecv(send_ptr, send_count, send_type, rank, tag,
- recv_ptr + rank * recv_chunk, recv_count, recv_type, rank, tag,
- comm, &status);
-
- i = 0;
- while (mask < num_procs) {
- dst = rank ^ mask;
- dst_tree_root = dst >> i;
- dst_tree_root <<= i;
- rank_tree_root = rank >> i;
- rank_tree_root <<= i;
- send_offset = rank_tree_root * send_chunk;
- recv_offset = dst_tree_root * recv_chunk;
-
- if (dst < num_procs) {
- MPI_Sendrecv(recv_ptr + send_offset, curr_count, send_type, dst,
- tag, recv_ptr + recv_offset, mask * recv_count,
- recv_type, dst, tag, comm, &status);
- MPI_Get_count(&status, recv_type, &last_recv_count);
- curr_count += last_recv_count;
- }
-
- if (dst_tree_root + mask > num_procs) {
- num_procs_completed = num_procs - rank_tree_root - mask;
- /* num_procs_completed is the number of processes in this
- subtree that have all the data. Send data to others
- in a tree fashion. First find root of current tree
- that is being divided into two. k is the number of
- least-significant bits in this process's rank that
- must be zeroed out to find the rank of the root */
-
- j = mask;
- k = 0;
- while (j) {
- j >>= 1;
- k++;
- }
- k--;
-
- offset = recv_chunk * (rank_tree_root + mask);
- tmp_mask = mask >> 1;
-
- while (tmp_mask) {
- dst = rank ^ tmp_mask;
-
- tree_root = rank >> k;
- tree_root <<= k;
-
- /* send only if this proc has data and destination
- doesn't have data. at any step, multiple processes
- can send if they have the data */
- if ((dst > rank)
- && (rank < tree_root + num_procs_completed)
- && (dst >= tree_root + num_procs_completed)) {
- MPI_Send(recv_ptr + offset, last_recv_count, recv_type, dst,
- tag, comm);
-
- /* last_recv_cnt was set in the previous
- receive. that's the amount of data to be
- sent now. */
- }
- /* recv only if this proc. doesn't have data and sender
- has data */
- else if ((dst < rank)
- && (dst < tree_root + num_procs_completed)
- && (rank >= tree_root + num_procs_completed)) {
- MPI_Recv(recv_ptr + offset,
- recv_count * num_procs_completed,
- recv_type, dst, tag, comm, &status);
- // num_procs_completed is also equal to the no. of processes
- // whose data we don't have
- MPI_Get_count(&status, recv_type, &last_recv_count);
- curr_count += last_recv_count;
- }
- tmp_mask >>= 1;
- k--;
- }
- }
-
- mask <<= 1;
- i++;
- }
-
- return success;
-}
