pshpstuningguidewp040105.doc
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1.0 Introduction
This paper is intended to help you tune and debug the performance of the IBM
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pSeries® High Performance Switch (HPS) on IBM Cluster 1600 systems. It is not intended to be
a comprehensive guide, but rather to help in initial tuning and debugging of performance issues.
Additional detailed information on the materials presented here can be found in sources noted in
the text and listed in section 7.0.
This paper assumes an understanding of MPI and AIX 5L™, and that you are familiar with and
have access to the Hardware Management Console (HMC) for pSeries systems.
This paper is divided into four sections. The first deals with HPS-specific tunables for tuning the
HPS subsystems. The second section deals with tuning AIX 5L and its components for optimal
performance of the HPS system. The third section deals with tuning various system daemons in
both AIX 5L and cluster environments to prevent impact on high-performance parallel
applications. The final section deals with debugging performance problems on the HPS.
Before debugging a performance problem in the HPS, review the HPS and AIX 5L tuning as well
as daemon controls. Many problems are specifically related to these subsystems. If a
performance problem persists after you follow the instructions in the debugging section, call IBM
service for additional tools and help.
We want to thank the following people in the IBM Poughkeepsie development organization for
their help in writing this paper:
Robert Blackmore
George Chochia
Frank Johnston
Bernard King-Smith
John Lewars
Steve Martin
Fernando Pizzano
Bill Tuel
Richard Treumann
