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ProfileBill Eckard

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Message 70117 - Posted: 19 Sep 2020, 14:34:39 UTC

I am processing GPU tasks on multiple GPU's and I also wanted to process CPU tasks. However, I received Separation tasks for the CPU which are better processed with the GPU. I there any way to limit the CPU processing to only tasks that specifically require processing this way, such as N-Body?
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ProfileKeith Myers
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Message 70119 - Posted: 19 Sep 2020, 21:05:05 UTC - in response to Message 70117.  

Create two different venues. One with cpu only and one with gpu only. Then run two BOINC clients with each one crunching either the cpu or gpu venue.
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ProfileBill Eckard

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Message 70120 - Posted: 20 Sep 2020, 17:57:23 UTC - in response to Message 70119.  

Thank you
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Diplomat

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Message 70125 - Posted: 24 Sep 2020, 3:26:34 UTC
Last modified: 24 Sep 2020, 3:29:18 UTC

How did you decide that NBody are better for CPU than Separation?

Pointswise Separation tasks grants you more credits: 227 credits for about 1,5 hrs of 1 CPU
While Nbody 8 CPUs for 15 min only 36 credits,

That's actually quite frustrating 8*15=120 min CPU time for only 36 credits =( very very conservative
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Profilemikey
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Message 70126 - Posted: 24 Sep 2020, 11:48:02 UTC - in response to Message 70125.  

How did you decide that NBody are better for CPU than Separation?

Pointswise Separation tasks grants you more credits: 227 credits for about 1,5 hrs of 1 CPU
While Nbody 8 CPUs for 15 min only 36 credits,

That's actually quite frustrating 8*15=120 min CPU time for only 36 credits =( very very conservative


But if you run 6 tasks in the same 1 1/2 hours you will get 216 credits
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Message 70128 - Posted: 24 Sep 2020, 12:11:21 UTC - in response to Message 70126.  
Last modified: 24 Sep 2020, 12:21:58 UTC

But if you run 6 tasks in the same 1 1/2 hours you will get 216 credits

Don't forget core count!

NBody: 6 tasks х 1 set of 8 CPUs yield 216 in ~1,5 hrs
Separation: 1 task * 8 CPUs yield 1816 in a same ~1,5 hrs
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eiernacken1983

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Message 70129 - Posted: 24 Sep 2020, 13:09:10 UTC - in response to Message 70125.  

How did you decide that NBody are better for CPU than Separation?

Pointswise Separation tasks grants you more credits: 227 credits for about 1,5 hrs of 1 CPU
While Nbody 8 CPUs for 15 min only 36 credits,

That's actually quite frustrating 8*15=120 min CPU time for only 36 credits =( very very conservative


I think he compared the time of the separation tasks when processed on GPU vs CPU.

Separation on GPU: 12 - 300 seconds (depending on the gpu)
Separation on CPU: 5400 seconds

less than 300 seconds < 5400 seconds --> so it is not efficient to process separation on CPU

As NBody can only be processed on the CPU he doesn't want to block his CPU with Separation units.

If you use a GPU the you don't care about the small amount of credits you can make with a CPU.
(Separation: 1 task * 8 CPUs yield 1816 in a same ~1,5 hrs --> separation on Radeon VII: 12 Secs/task --> 300 Tasks per hour --> 450 tasks per 1.5 hours = 68,100 credits)

So if you want to maximize scientific output (not credits) for the project you should do separation on GPU and NBody on CPU. I think this was the intention of Bill Eckard. If yes, I agree with him :-)
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Message boards : Number crunching : Selecting tasks for CPU

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