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Subject: [OMPI users] alltoall messages > 2^26
From: Michael Di Domenico (mdidomenico4_at_[hidden])
Date: 2011-04-04 17:16:55


Has anyone seen an issue where OpenMPI/Infiniband hangs when sending
messages over 2^26 in size?

For a reason i have not determined just yet machines on my cluster
(OpenMPI v1.5 and Qlogic Stack/QDR IB Adapters) is failing to send
array's over 2^26 in size via the AllToAll collective. (user code)

Further testing seems to indicate that an MPI message over 2^26 fails
(tested with IMB-MPI)

Running the same test on a different older IB connected cluster seems
to work, which would seem to indicate a problem with the infiniband
drivers of some sort rather then openmpi (but i'm not sure).

Any thoughts, directions, or tests?