Kay Diederichs Kay.Diederichs at
Wed May 8 06:36:18 EST 1996

I have made the same experience on the university computing centre 10-processor
R8000 PowerChallenge, which mostly runs at a load average of around 30. When I
performed the tests (benchmark1 and benchmark2), the system was at IRIX 6.0.1.

If I only look at the CPU time reported at the end of the job, X-PLOR appears
to run slightly faster if more than one processor is used. However, the wall
clock time actually increases by a factor of 3 up to 10 (probably depending on
the load). I never had the opportunity to test on an otherwise idle

What I now do is use NUMTHREADS of 1 and run several jobs at the same time (if
it makes sense for the project). Due to the large size of the program and data
area, X-PLOR gets most of the CPU cycles. Using one processor, the wall clock
time is about half of that required on our SGI R4400 200MHz workstation.

Pretty sobering multiprocessing experience.
Kay Diederichs                    
email: Kay.Diederichs at     Tel: +49 7531 88 4049  Fax: 3183
Fakultaet fuer Biologie, Universitaet Konstanz 
Postfach 5560 (M656), D-78434 Konstanz, Germany

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