Xavier,

i confirm there is a bug when using MPI_ANY_SOURCE with Open MPI
configure'd with --enable-heterogeneous

i made https://github.com/open-mpi/ompi/pull/4501 in order to fix
that, and will merge and backport once reviewed


Cheers,

Gilles

On Mon, Nov 13, 2017 at 8:46 AM, Gilles Gouaillardet
<gilles.gouaillar...@gmail.com> wrote:
> Xavier,
>
> thanks for the report, i will have a look at it.
>
> is the bug triggered by MPI_ANY_SOURCE ?
> /* e.g. does it work if you MPI_Irecv(..., myrank, ...) ? */
>
>
> Unless ubuntu wants out of the box support between heterogeneous nodes
> (for example x86_64 and ppc64),
> there is little to no point in configuring Open MPI with the
> --enable-heterogeneous option */
>
>
> Cheers,
>
> Gilles
>
> On Mon, Nov 13, 2017 at 7:56 AM, Xavier Besseron <xavier.besse...@uni.lu> 
> wrote:
>> Dear all,
>>
>> I want to share with you the follow issue with the OpenMPI shipped with the
>> latest Ubuntu Artful. It is OpenMPI 2.1.1 compiled with option
>> --enable-heterogeneous.
>>
>> Looking at this issue https://github.com/open-mpi/ompi/issues/171, it
>> appears that this option is broken and should not be used.
>> This option is being used in Debian/Ubuntu since 2010
>> (http://changelogs.ubuntu.com/changelogs/pool/universe/o/openmpi/openmpi_2.1.1-6/changelog)
>> and is still used so far. Apparently, nobody complained so far.
>>
>> However, now I complain :-)
>> I've found a simple example for which this option causes invalid results in
>> OpenMPI.
>>
>>
>> int A = 666, B = 42;
>> MPI_Irecv(&A, 1, MPI_INT, MPI_ANY_SOURCE, tag, comm, &req);
>> MPI_Send(&B, 1, MPI_INT, my_rank, tag, comm);
>> MPI_Wait(&req, &status);
>>
>> # After that, when compiled with --enable-heterogeneous, we have A != B
>>
>> This happens with just a single process. The full example is in attachment
>> (to be run with "mpirun -n 1 ./bug_openmpi_artful").
>> I extracted and simplified the code from the Zoltan library with which I
>> initially noticed the issue.
>>
>> I find it annoying that Ubuntu distributes a broken OpenMPI.
>> I've also tested OpenMPI 2.1.1, 2.1.2 and 3.0.0 and using
>> --enable-heterogeneous causes the bug systematically.
>>
>>
>> Finally, my points/questions are:
>>
>> - To share with you this small example in case you want to debug it
>>
>> - What is the status of issue https://github.com/open-mpi/ompi/issues/171 ?
>> Is this option still considered broken?
>> If yes, I encourage you to remove it or mark as deprecated to avoid this
>> kind of mistake in the future.
>>
>> - To get the feedback of OpenMPI developers on the use of this option, which
>> might convince the Debian/Ubuntu maintainer to remove this flag.
>> I have opened a bug on Ubuntu for it
>> https://bugs.launchpad.net/ubuntu/+source/openmpi/+bug/1731938
>>
>>
>> Thanks!
>>
>> Xavier
>>
>>
>> --
>> Dr Xavier BESSERON
>> Research associate
>> FSTC, University of Luxembourg
>> Campus Belval, Office MNO E04 0415-040
>> Phone: +352 46 66 44 5418
>> http://luxdem.uni.lu/
>>
>>
>> _______________________________________________
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>> users@lists.open-mpi.org
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