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LeMieux Skates Faster: Supercomputer Tuning Yields Major Speed Improvement

The Tereascale Computing System at Pittsburgh Supercomputing Center

LeMieux: The Terascale Computing System

PITTSBURGH, June 25, 2002 — According to the 19th edition of the TOP500 list of the world's fastest computers, released last week at an international conference in Heidelberg, the Pittsburgh Supercomputing Center's HP/Compaq system ranks number three with a rating of 4.463 TeraFlops (trillions of floating-point operations per second) according to the LINPACK benchmark.

For the 18th edition of the list, produced November of last year — just after the Pittsburgh machine was installed — the rating was 4.059 TeraFlops. The 10 percent improvement in performance came not through additional hardware but rather through optimization of system software to exploit advanced and unique features of the Quadricsª network which connects the 760 nodes of the machine to make it into a single system.

Dick Foster of HP's High Performance Computing Expertise Center in Massachusetts and Tim Reddin in the High Performance Technical Computing Engineering group in Galway worked to identify and implement subtle software changes to optimize inter-process communications yielding the overall 10 percent speed increase. "This increase alone," notes Reddin, "is equivalent to the performance rating of the 124th placed system in the latest TOP500 list."

"For a system the size of LeMieux (network name of the system, 'the best' in French), with 3,000 compute processors, 10 percent is a big number." says Jim Kasdorf, director of special projects at PSC. "In effect, we've gained 300 more processors through this effort. I believe that such improvements through software are frequently under-appreciated."

LeMieux, also known as TCS-1 (for Tera Scale Computing System -1), is funded principally by the National Science Foundation through its Advanced Computational Infrastructure and Research division.

For more information about the Terascale Computing System see:

The Pittsburgh Supercomputing Center is a joint effort of Carnegie Mellon University and the University of Pittsburgh together with the Westinghouse Electric Company. It was established in 1986 and is supported by several federal agencies, the Commonwealth of Pennsylvania and private industry.


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Michael Schneider
Pittsburgh Supercomputing Center

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