Messages in this thread | | | Date | Wed, 05 Dec 2007 17:16:51 -0500 | From | Jie Chen <> | Subject | Re: Possible bug from kernel 2.6.22 and above, 2.6.24-rc4 |
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Ingo Molnar wrote: > * Jie Chen <chen@jlab.org> wrote: > >>> sorry to be dense, but could you give me instructions how i could >>> remove the affinity mask and test the "barrier overhead" myself? I >>> have built "pthread_sync" and it outputs numbers for me - which one >>> would be the barrier overhead: Reference_time_1 ? >> To disable affinity, do configure --enable-public-release >> --disable-thread_affinity. You should see barrier overhead like the >> following: Computing BARRIER time >> >> Sample_size Average Min Max S.D. Outliers >> 20 19.486162 19.482250 19.491400 0.002740 0 >> >> BARRIER time = 19.486162 microseconds +/- 0.005371 >> BARRIER overhead = 8.996257 microseconds +/- 0.006575 > > ok, i did that and rebuilt. I also did "make check" and got > src/pthread_sync which i can run. The only thing i'm missing, if i run > src/pthread_sync, it outputs "PARALLEL time": > > PARALLEL time = 22.486103 microseconds +/- 3.944821 > PARALLEL overhead = 10.638658 microseconds +/- 10.854154 > > not "BARRIER time". I've re-read the discussion and found no hint about > how to build and run a barrier test. Either i missed it or it's so > obvious to you that you didnt mention it :-) > > Ingo
Hi, Ingo:
Did you do configure --enable-public-release? My qmt is for qcd calculation (one type of physics code). Without the above flag one can only test PARALLEL overhead. Actually the PARALLEL benchmark has the same behavior as the BARRIER. Thanks.
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