A new preview release of MPICH, 3.3b3, 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 in beta stages, meaning there are known build issues and
bugs, but most tests and common benchmarks will complete on 64-bit Linux
systems. Since 3.3b2, there have been more stability improvements, bug
fixes, and code cleanup. PMIx client library support is added in CH4 to
support launching with a compatible PMIx server.
Also in this release is a reorganization of MPI collectives to make it
easier to integrate new algorithms. A new framework is added to enable
collective algorithms on either generic or device-specific functionality
using a C++-template style system. Support is added for creating
communicators based on hardware and network topology hints, and SLURM
integration in Hydra is updated to work with the latest node list
format. 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.
# Added support for splitting communicators based on hardware
topology using info hints.
# 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.
# 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.
# 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..v3.3b3
A list of bugs that have been fixed is available at the following
link:
https://github.com/pmodels/mpich/milestone/25?closed=1
