> >>> It seems that the calls to collective communication are not
> >>> returning for some MPI processes, when the number of processes is
> >>> greater or equal to 5. It's reproduceable, on two different
> >>> architectures, with two different versions of OpenMPI (1.3.2 and
> >>> 1.3.3). It was working correctly with OpenMPI version 1.2.7.
> >> Does it work if you turn off the shared memory transport layer;
> >> that is,
> >> mpirun -n 6 -mca btl ^sm ./testmpi
> > Yes it does, on both my configurations (AMD and Intel processor).
> > So it seems that the shared memory synchronization process is
> > broken.
> Presumably that is this bug:
Yes it is.
> I also found by trial and error that increasing the number of fifos, eg
> -mca btl_sm_num_fifos 5
> on a 6-processor job, apparently worked around the problem.
> But yes, something seems broken in OpenMP shared memory transport with
> gcc 4.4.x.
Yes, same for me: -mca btl_sm_num_fifos 5 worked.
Thanks for your answer Jonathan.
If I may help the developpers in any way to track this bug get into
contact with me.