[mvapich-discuss] thread safety over IB

[Krishna Kandalla]

Hello,
         We do offer THREAD_MULTIPLE support for IB in MVAPICH2. Our
default behavior is also consistent with MPICH2's "runtime" threading
option -- the threading level is determined by the input parameters to
MPI_Init_thread().
         You do not have to use any additional configuration flags to turn
on threading support in MV2-1.7. You just have to make sure you request for
THREAD_MULTIPLE during Init. (Your sample code seems to be doing that
already)  However, at job launch time, you may have to set
processor-affinity to 0, using the MV2_ENABLE_AFFINITY=0 option. Please
refer to section 6.14 in our userguide (
http://mvapich.cse.ohio-state.edu/support/user_guide_mvapich2-1.7.html#x1-700006.14)
for more information. Please let us know if you have any other questions.

Thanks,
Krishna


On Thu, Nov 3, 2011 at 7:49 PM, Marquez, Andres <andres.marquez at pnnl.gov>wrote:

>   All,
>
> we are trying to build the latest version of mvapich2-1.7  with following
> configuration (OFED stack is under /usr/lib64):
>
> configure --prefix=/home/d3m799/mvapich2-1.7/install --enable-shared
> --enable-threads=runtime  --enable-debuginfo --with-pm=none
> --with-pmi=slurm  2>&1 | tee c.txt
>
> Please find the configure, make and install logs attached.
>
> Running the following little program fails the assertion:
> ----------------------------
> #if HAVE_CONFIG_H
> #   include "config.h"
> #endif
>
> #include <mpi.h>
> #include <assert.h>
> #include <pthread.h>
>
> int main(int argc, char **argv)
> {
>   int provided;
>   MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);
>   assert(provided == MPI_THREAD_MULTIPLE);
>
>   MPI_Finalize();
>   return 0;
> }
>
> The latest mpich2-1.4.1p1 build over default ch3 succeeds with this
> program.
>
> The mvapcih2-1.7 README states:
> quote
> --enable-threads - Build MPICH2 with support for multi-threaded
>                     applications. Only the sock and nemesis channels
>                     support MPI_THREAD_MULTIPLE.
> unquote
>
> My understanding was that MPI_THREAD_MULTIPLE over IB is supported?
> Please advise.
>
> Thanks,
>
>
>
>
>
>
>
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>
>
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