Dear OpenMPI developers,
we found a strange behavior when using MPI-RMA passive target and OpenMPI
(versions 1.8.3 and 1.10.2). We don't see any problem when using MPICH.
This is a small example on what we want to do:
===================
program rma_openmpi
use mpi
integer :: nproc, rank, ierr
integer :: win, request, size
INTEGER(kind=mpi_address_kind) :: size_aint, disp_aint
integer, DIMENSION(:), ALLOCATABLE :: meta, recv
call MPI_INIT(ierr)
call MPI_COMM_SIZE(MPI_COMM_WORLD, nproc, ierr)
call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr)
size=100
ALLOCATE(meta(size),recv(size))
meta(:) = rank
recv(:) = -1
size_aint = size*4
call
MPI_WIN_CREATE(meta,size_aint,4,MPI_INFO_NULL,MPI_COMM_WORLD,win,ierr)
call MPI_WIN_LOCK_ALL(MPI_MODE_NOCHECK, win, ierr)
disp_aint = 0
CALL MPI_RGET(recv,size,MPI_INTEGER,MOD(rank+1,2),disp_aint,&
size,MPI_INTEGER,win,request,ierr)
IF (ierr .NE. 0) STOP "error mpi_rget"
CALL MPI_WAIT(request,MPI_STATUS_IGNORE,ierr)
IF (ierr .NE. 0) STOP "error mpi_wait"
! call MPI_Win_flush_all(win,ierr)
print *,rank,"=",recv(1)
call MPI_WIN_UNLOCK_ALL(win, ierr)
call MPI_WIN_FREE(win,ierr)
DEALLOCATE(meta)
call MPI_FINALIZE(ierr)
end program rma_openmpi
===================
You can run with 2 ranks.
As you can see it is a simple rget operation from the neighbor rank.
However, it seems that the communications doesn't complete after the
mpi_wait. Indeed we get:
0 = -1
1 = -1
while it should be:
0 = 1
1 = 0
The code works as we want by uncommenting the flush operation, but we would
expect the same behavior with such a synchronization.
Thanks for your help!
Best regards,
Alfio
