[Llvm-bgq-discuss] MPI3 in bgclang (r264155-20160323)

[Hal Finkel]

Hi everyone,

Starting with today's nightly build, r264155-20160323, MPI v3 support is available with bgclang. Please try it out. The build is based on Rob Latham's MPICH-BlueGene fork (which is mostly mpich-3.1.4 plus BG/Q I/O work from mpich-3.2). This will give you, for example, an MPI_Fetch_and_op based on the underlying PAMI implementation.

There are four versions included (legacy vs. non-legacy) x (regular vs. ndebug). So we now have:

ls /soft/compilers/bgclang/${rev}/mpi

bgclang - System fine-grained-locking MPI
bgclang.legacy - System legacy MPI

bgclang-mpi3 - MPI3 fine-grained-locking MPI
bgclang-mpi3.legacy - MPI3 legacy MPI
bgclang-mpi3.legacy.ndebug - MPI3 legacy MPI (optimized)
bgclang-mpi3.ndebug - MPI3 fine-grained-locking MPI (optimized)

As with the regular system versions, the fine-grained locking versions should be best when running with MPI_THREAD_MULTIPLE, and the legacy version is probably better otherwise. For production, linking with the ndebug versions might bring some benefit, but for development, use the non-ndebug builds.

For those maintaining their own installs, there is now a bgclang-mpich3 rpm that supplements the others, see: http://www.mcs.anl.gov/~hfinkel/bgclang/#r264155-20160323

Thanks again,
Hal

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory