[mpich-announce] MPICH 4.1rc1 released

[Raffenetti, Ken]

A new release candidate of MPICH, 4.1rc1, is now available for download. Major features in this release include:

* Standalone libpmi
* Independent use of MPICH testsuite
* Experimental MPIX stream prototypes to support explicit threading context and asynchronous enqueue to GPU streams. Both CUDA and HIP are supported.
* Significant refactor in PMI and Hydra

At this stage, only critical bugs will be fixed before the 4.1 GA release. Please give it a try!

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

Regards,
The MPICH team

===============================================================================
Changes in 4.1
===============================================================================

# Thread-cs in ch4 changed to per-vci.

# Testsuite (test/mpi) is configured separately from mpich configure.

# Added options in autogen to accelerate CI builds, including using pre-built
sub-modules. Added -yaksa-depth option to generate shallower yaksa pup code
for faster build and smaller binaries.

# Support singleton init using hydra.

# On OSX, link option flat_namespace is no longer turned on by default.

# Generate mpi.mod Fortran interfaces using Python 3. For many compilers,
including gfortran, flags such as -fallow-mismatched-args is no longer
necessary.

# Fixed message queue debugger interface in ch4.

# PMI (src/pmi) is refactored as a subdir and can be separately distributed.

# Added MPIX_Comm_get_failed.

# Experimental MPIX stream API to enable explicit thread contexts.

# Experimental MPIX gpu enqueue API. It currently only supports CUDA streams.

# Delays GPU resource allocation in yaksa.

# CH3 nemesis ofi netmod is removed.

# New collective algorithms. All collective algorithms are listed in
src/mpi/coll/coll_algorithms.txt

# Removed hydra2. We will port unique features of hydra2, including
tree-launching, to hydra in the future release.

# Added in-repository wiki documentation.

# Added stream workq to support optimizations for enqueue operations.

# Better support for large count APIs by eliminating type conversion issues.

# Hydra now uses libpmi (src/pmi) for handling PMI messages.

# Many bug fixes and enhancements.

A full list of changes since 4.0.3 can be found here: https://github.com/pmodels/mpich/compare/v4.0.3...v4.1rc1