Hello!
I would like to report a bug in Open MPI 1.7.4 when compiled with
--enable-mpi-thread-multiple.
The bug can be reproduced with the following test program (mpi-send-recv.c):
===========================================
#include <mpi.h>
#include <stdio.h>
int main() {
MPI_Init(NULL, NULL);
int rank;
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
printf("Rank %d at start\n", rank);
if (rank)
MPI_Send(NULL, 0, MPI_CHARACTER, 0, 0, MPI_COMM_WORLD);
else
MPI_Recv(NULL, 0, MPI_CHARACTER, 1, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("Rank %d at end\n", rank);
MPI_Finalize();
return 0;
}
===========================================
With Open MPI 1.7.4 compiled with --enable-mpi-thread-multiple, the
test program above fails like this:
$ mpirun -np 2 ./a.out
Rank 0 at start
Rank 1 at start
[elias-p6-2022scm:2743] *** An error occurred in MPI_Recv
[elias-p6-2022scm:2743] *** reported by process
[140733606985729,140256452018176]
[elias-p6-2022scm:2743] *** on communicator MPI_COMM_WORLD
[elias-p6-2022scm:2743] *** MPI_ERR_TYPE: invalid datatype
[elias-p6-2022scm:2743] *** MPI_ERRORS_ARE_FATAL (processes in this
communicator will now abort,
[elias-p6-2022scm:2743] *** and potentially your MPI job)
Steps I use to reproduce this in Ubuntu:
(1) Download openmpi-1.7.4.tar.gz
(2) Configure like this:
./configure --enable-mpi-thread-multiple
(3) make
(4) Compile test program like this:
mpicc mpi-send-recv.c
(5) Run like this:
mpirun -np 2 ./a.out
This gives the error above.
Of course, in my actual application I will want to call
MPI_Init_thread with MPI_THREAD_MULTIPLE instead of just MPI_Init, but
that does not seem to matter for this error; the same error comes
regardless of the way I call MPI_Init/MPI_Init_thread. So I just put
MPI_Init in the test code above to make it as short as possible.
Do you agree that this is a bug, or am I doing something wrong?
Any ideas for workarounds to make things work with
--enable-mpi-thread-multiple? (I do need threads, so skipping
--enable-mpi-thread-multiple is probably not an option for me.)
Best regards,
Elias
