[mesa-users] Multi-threading in release v4442

David Chamulak dchamulak at gmail.com
Wed Sep 5 16:18:59 EDT 2012


I'm a long time reader first time poster to this mailing list.

I noticed release 4442 to be slower then previous releases. So I
deiced to run a test. I compiled and ran the star/work directory
without any changes to the source / inlist files. What I did change
was $OMP_NUM_THREADS from 1 to 8 (I'm running on a newer i7 so that
should be fine). I did time ./rn to time the run and found the

1 thread
real    27m52.295s
user    24m52.601s
sys     0m6.104s

4 threads
real    33m50.369s
user    81m16.881s
sys     0m16.449s

8 threads
real    38m57.424s
user    168m24.087s
sys     0m29.390s

Does anyone else find multiple threads make the run slower?

-David Chamulak

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