Commit 266085d6 authored by Eisenhauer, Greg's avatar Eisenhauer, Greg
Browse files

Split MPI_COMM_WORLD by role in MultiStreamBiDir test for MPMD launches 



When launched via a single MPMD srun invocation, all three roles
(server, client0, client1) share MPI_COMM_WORLD. Use MPI_Comm_split
to give each role its own communicator so ADIOS operations are
scoped correctly.

Co-Authored-By: default avatarClaude Opus 4.6 (1M context) <noreply@anthropic.com>
parent b967b51e

testing/adios2/engine/staging-common/TestMultiStreamBiDir.cpp

+14 −3
Original line number Diff line number Diff line
@@ -168,12 +168,22 @@ int main(int argc, char **argv) 
#if ADIOS2_USE_MPI

    int provided;

    MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);

    MPI_Comm_rank(MPI_COMM_WORLD, &mpiRank);

    MPI_Comm_size(MPI_COMM_WORLD, &mpiSize);



    // Split MPI_COMM_WORLD by role so that each role group gets its own

    // communicator.  This allows the test to be launched either as three

    // separate MPI jobs or in a single MPMD srun invocation.

    MPI_Comm roleComm;

    int color = role + 2; // map {-1,0,1} -> {1,2,3} so every color is non-negative

    int key;

    MPI_Comm_rank(MPI_COMM_WORLD, &key);

    MPI_Comm_split(MPI_COMM_WORLD, color, key, &roleComm);



    MPI_Comm_rank(roleComm, &mpiRank);

    MPI_Comm_size(roleComm, &mpiSize);

#endif



#if ADIOS2_USE_MPI

    adios2::ADIOS adios(MPI_COMM_WORLD);

    adios2::ADIOS adios(roleComm);

#else

    adios2::ADIOS adios;

#endif
@@ -194,6 +204,7 @@ int main(int argc, char **argv) 
    }



#if ADIOS2_USE_MPI

    MPI_Comm_free(&roleComm);

    MPI_Finalize();

#endif