[mpich-announce] Announcing the availability of MPICH 3.3rc1

[Raffenetti, Kenneth J.]

A new release candidate of MPICH, 3.3rc1, is now available for download. 
MPICH 3.3 contains a new (non-default) device layer implementation – 
CH4. CH4 is designed for low software overheads to better exploit 
next-generation hardware. An OFI (http://libfabric.org) or UCX 
(http://openucx.org) library is required to build CH4. Example configure 
lines:

./configure --with-device=ch4:ofi --with-libfabric=<path/to/ofi/install>
./configure --with-device=ch4:ucx --with-ucx=<path/to/ucx/install>

CH4 is still experimental, meaning there are known build issues and 
bugs, but most tests and common benchmarks will complete on 64-bit Linux 
systems. Since 3.3b3, there have been more stability improvements, bug 
fixes, and code cleanup. Also new are improvements to 
MPI_THREAD_MULTIPLE in CH4 through new thread safety models at the 
Virtual Network Interface (VNI) level. This introduces two new models 
that leverage work-queues to offload operations and improve scalability 
under contention.

You can find the release on our downloads page (www.mpich.org/downloads).

Regards,
The MPICH team

===============================================================================
                                Changes in 3.3
===============================================================================

  # CH4 Device: A new device layer implementation designed for low
    software overheads. CH4 has experimental support for OFI and UCX
    network libraries, and POSIX shared memory. Thanks to Intel,
    Mellanox, and RIKEN AICS for participating in the CH4 coding
    effort.

  # Fixed SLURM integration in Hydra for new node list format.

  # Added support for PMIx (https://pmix.github.io/pmix/) client
    library in CH4 netmods. Note that you must use a compatible PMIx
    server in this configuration.

  # Better organization of collectives in the MPI layer. The new
    scheme, which de-couples implementation from selection logic,
    enables easier integration of additional algorithms.

  # TSP collectives framework: A C++-template style framework for
    collective algorithms is added to allow single collective
    implementation to move data over generic or device-specific
    transport functions.

  # Improvements to derived datatype testing (DTPools -
    https://wiki.mpich.org/mpich/index.php/DTPools).

  # Added new "non-catastrophic" error codes to expose internal
    resource exhaustion.

  # Added info hints to MPI_Comm_split_type to support splitting
    communicators by machine topology. Both on-node (socket, core,
    etc.) and off-node (switch-level) hints are defined.

  # Improvements to MPI_THREAD_MULTIPLE in CH4 through new thread
    safety models at the Virtual Network Interface (VNI) level. This
    introduces two new models that leverage work-queues to offload
    operations and improve scalability under contention.

  # Message Driven Thread Activation (MDTA). An alternative locking
    model is defined for MPI_THREAD_MULTIPLE in CH4.

  # Added PMI usage optimizations for business card exchange in CH4
    netmods.

  # Improvements on MPI_Abort. MPI_Abort invoked on subcommunicators will
    only abort the connected processes within that communicator.

  # Cleanup of whitespace (ch3 excluded) using the
    maint/code-cleanup.sh script. For instructions on how to update
    PRs/branches based on MPICH before the cleanup, see
    https://github.com/pmodels/mpich/wiki/Code-Cleanup-Procedure.

  # Removed the PAMI device and poe PMI client.

  # C99 compiler support is now required to build MPICH.

  # Several other minor bug fixes, memory leak fixes, and code cleanup.

    A full list of changes is available at the following link:

      http://git.mpich.org/mpich.git/shortlog/v3.2..v3.3rc1

    A list of bugs that have been fixed is available at the following
    link:

      https://github.com/pmodels/mpich/milestone/25?closed=1