GPU uses large CPU time

Message boards : Number crunching : GPU uses large CPU time

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Chris

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Message 1320906 - Posted: 28 Dec 2012, 19:04:37 UTC

I have a new GTX 650 installed (driver 310.70). It seems to be working great. Plenty of good WUs with few errors.

It is, however, using more than .4 cpu cores. Is this to be expected with the faster GPU? It does seem higher than most when I searched.

Everything is stock seti except the environmental variable.

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Josef W. Segur
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Message 1320959 - Posted: 28 Dec 2012, 21:15:06 UTC - in response to Message 1320906.

I have a new GTX 650 installed (driver 310.70). It seems to be working great. Plenty of good WUs with few errors.

It is, however, using more than .4 cpu cores. Is this to be expected with the faster GPU? It does seem higher than most when I searched.

Everything is stock seti except the environmental variable.

That's the server estimate of how much CPU will be needed, it is not actually using that much CPU time. For any task, divide the final CPU time by Run time to get the actual CPU fraction used. It looks to be in the .15 to .26 range for your system actually.

The BOINC server code gets that estimate from the GFLOPS formula for the GPU compared to the Whetstone benchmark for the CPU, with some project-supplied modifying terms. A GPU with higher GFLOPS does increase the CPU fraction estimate, an infinitely fast GPU would mean that all the run time would be on the CPU and the estimate would be 1.0.
                                                                Joe

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Message boards : Number crunching : GPU uses large CPU time


 
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