QLogic OFED+ Host Software User Guide, Rev. B

6 Performance Scaled
Messaging
Introduction
Performance Scaled Messaging (PSM) provides support for full Virtual Fabric
(vFabric) integration, allowing users to specify InfiniBand Service Level (SL) and
Partition Key (PKey), or to provide a configured Service ID (SID) to target a
vFabric. Support for using InfiniBand path record queries to the QLogic Fabric
Manager during connection setup is also available, enabling alternative switch
topologies such as Mesh/Torus. Note that this relies on the Distributed SA cache
from FastFabric.
All PSM enabled MPIs can leverage these capabilities transparently, but only two
MPIs (QLogic MPI and OpenMPI) are configured to support it natively. Native
support here means that MPI specific mpirun switches are available to
activate/deactivate these features. Other MPIs will require use of environment
variables to leverage these capabilities. With MPI applications, the environment
variables need to be propagated across all nodes/processes and not just the node
from where the job is submitted/run. The mechanisms to do this are MPI specific,
but for two common MPIs the following may be helpful:
• OpenMPI: Use –x ENV_VAR=ENV_VAL in the mpirun command line.
Example:
mpirun –np 2 –machinefile machinefile -x
PSM_ENV_VAR=PSM_ENV_VAL prog prog_args
• MVAPICH2: Use mpirun_rsh to perform job launch. Do not use mpiexec
or mpirun. Specify the environment variable and value in the mpirun
command line before the program argument.
Example:
mpirun_rsh –np 2 –hostfile machinefile PSM_ENV_VAR=PSM_ENV_VAL
prog prog_args
Some of the features available require appropriate versions of associated
software and firmware for correct operation. These requirements are listed in the
relevant sections.
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