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Message boards : Number crunching : GERARD_CXCL12 : unusual CPU time used

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Message 39306 - Posted: 25 Dec 2014 | 18:57:18 UTC

Dear all,

Merry Christmas and thanks to Gerard for releasing new units to crunch.

I looked at my host stats and noticed an unusual CPU time use for GERARD_CXCL12 units when compared to other units ?

Source data :

I only analyzed page 1, but I found that CPU time / GPU time is :
- usually (SDOERR_BARNA5) : 7% (in the range 5%-9%)
- for GERARD_CXCL12 : 23% (in the range 21%-24%)

System : 2xGTX770+1xG750Ti, Ubuntu 14.04.1 64 bits, BOINC 7.3.15, Nvidia 343.22 (only crunched on GTX770s, not yet on GTX750Ti)

Any reason why CPU usage is that high for these particular units ?

Best regards,


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Message 39366 - Posted: 2 Jan 2015 | 12:16:31 UTC - in response to Message 39306.

The CXCL12 WUs contain relatively few small molecules with fewer atoms (about 30k) than typical long-runs (70k - 80k). The less atoms a WU contains, the faster each time step is computed (if everything else, including the scientific model is comparable). For my GTX970 it's about 2 ms per time step, compared to e.g. 5 ms for a SDOERR_BARNA5. The overall runtime of these WUs is comparable to other long runs, which means they must contain more time steps. Some CPU intervention is required after each time step, I think, or at least proportionally to the number of time steps. That's a good reason for the CPU usage of these smaller WUs to be higher :)

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Message boards : Number crunching : GERARD_CXCL12 : unusual CPU time used