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What's New in LAM 7.1.2

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LAM 7.1 provides a number of new features designed to improve both the user experience and performance of MPI applications. As with any MPI implementation, no changes to applications should be needed to take advantage of the new features introduced in 7.1.

SSI modules as Dynamic Shared Objects (DSO)
SSI modules can be built as part of the MPI libraries that are linked into user applications or as standalone dynamic shared objects (DSOs). When compiled as DSOs, all SSI modules are installed in $prefix/lib/lam. New modules can be added to or removed from an existing LAM installation simply by putting new DSOs in that directory (there is no need to recompile or relink user applications).

Infiniband Support
With LAM/MPI 7.1 it is possible to make use of the high bandwidth and low latency of Infiniband networks. LAM/MPI provides Infiniband support using the
Mellanox Verbs Interface (VAPI). Currenly LAM/MPI uses the Infiniband send/receive protocol for tiny messages and RDMA for long messages. RDMA for tiny messages will be expored in the near future.

Integration with SLURM
LAM/MPI now provides support for
SLURM batch queue systems. SLURM contains a native system for launching applications across the nodes that it manages. The LAM/MPI SLURM boot module when used will automatically make use of SLURM's native job interface to start LAM daemons.

BProc 4.0 Support
BProc is a set of kernel modifications, utilities and libraries which allow a user to start processes on other machines in a Beowulf-style cluster. LAM/MPI 7.1 now also supports BProc 4.0.

Improved Collectives
Several collective algorithms have been made SMP aware, to exploit the performace of clusters of SMPs. Shared memory collective algorithms have also been introduced to take advantage of the scenario when all processes are on the same node. By default, usage of shared memory collectives is turned off. See the User Documentation on how to turn this feature on at runtime. Collective operations are now also supported on inter-communicators.

Improved Myrinet Support
LAM/MPI 7.1 now addresses all known
Myrinet RPI (gm module) problems, such as - fixing the incorrect handling of timed out packets, performace improvement by removing the "short" message size and just keeping "tiny" and "long" sizes, allowing non-default location of gm library to be specified during installation and so on. Please have a look at the HISTORY file in the LAM/MPI source for an exhaustive list of improvements.