Performance Studies using PSTSWM

SGI/Cray Research Origin2000 Protocol Performance

(MPI/SHMEM Comparison - April 22, 1999)

The SGI/Cray Research Origin2000 is a Nonuniform Access Memory Access (NUMA) shared memory architecture. We looked at the protocol sensitivities of two different message-passing libraries: MPI and an application-specific library built using the SHMEM one-sided communication operations get and put.

The MPI and SHMEM communication protocols are not directly comparable, but some general conclusions can be drawn from the protocol sensitivity experiments. Similarities between the MPI and SHMEM results are as follows:

• a1 (nonblocking send) protocol is often optimal.
• The general rule of thumb that transpose algorithms have similar optimal protocols holds for both libraries.

Significant differences include the following:

• Overlap techniques are generally useful for SHMEM, but have only limited utility for MPI implementations.

PSTSWM Performance Page

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Patrick H. Worley / ( worleyph@ornl.gov)
Last Modified Monday, 15-Jul-2002 10:08:32 EDT.
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