On 05/05/2015 05:03 AM, David Froger wrote:

I did not tried mpich3.2b2 yet (will do tomorrow), but I've ask another question here, just on the time to execute MPI_Barrier: http://stackoverflow.com/questions/30039802/what-control-mpi-barrier-time-to...

Seems that that was why `bench_mpi.cxx` was slow. The underlying issue is that recent MPICH causes processes to busy poll for incoming messages. In over-subscription scenarios, this can have significant performance implications. There is a ongoing work to address the busy polling issue for MPICH 3.3. In the interim, our advice is to not oversubscribe processes for the available hardware resources.

Ken _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss