-#include "colls_private.h"
-
-// Allgather-Non-Topoloty-Scecific-Logical-Ring algorithm
-int
-smpi_coll_tuned_allgather_lr(void *sbuf, int scount, MPI_Datatype stype,
- void *rbuf, int rcount, MPI_Datatype rtype,
- MPI_Comm comm)
-{
- MPI_Aint rextent, sextent;
- MPI_Status status;
- int i, to, from, rank, size;
- int send_offset, recv_offset;
- int tag = COLL_TAG_ALLGATHER;
-
- rank = smpi_comm_rank(comm);
- size = smpi_comm_size(comm);
- rextent = smpi_datatype_get_extent(rtype);
- sextent = smpi_datatype_get_extent(stype);
-
- // irregular case use default MPI fucntions
- if (scount * sextent != rcount * rextent) {
- XBT_WARN("MPI_allgather_lr use default MPI_allgather.");
- smpi_mpi_allgather(sbuf, scount, stype, rbuf, rcount, rtype, comm);
- return MPI_SUCCESS;
- }
-
- // topo non-specific
- to = (rank + 1) % size;
- from = (rank + size - 1) % size;
-
- //copy a single segment from sbuf to rbuf
- send_offset = rank * scount * sextent;
- smpi_mpi_sendrecv(sbuf, scount, stype, rank, tag,
- (char *) rbuf + send_offset, rcount, rtype, rank, tag,
- comm, &status);
-
- //start sending logical ring message
- int increment = scount * sextent;
- for (i = 0; i < size - 1; i++) {
- send_offset = ((rank - i + size) % size) * increment;
- recv_offset = ((rank - i - 1 + size) % size) * increment;
- smpi_mpi_sendrecv((char *) rbuf + send_offset, scount, stype, to, tag + i,
- (char *) rbuf + recv_offset, rcount, rtype, from, tag + i,
- comm, &status);
- }
-
- return MPI_SUCCESS;
-}
