BOINC not downloading GPU WUs


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Message boards : Number crunching : BOINC not downloading GPU WUs

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Profile lupo
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Message 1033454 - Posted: 17 Sep 2010, 3:57:29 UTC
Last modified: 17 Sep 2010, 4:37:00 UTC

Hey everyone. I noticed something strange after the recent outage. My system has been running for the past few hours and during that time I can see it has downloaded a few WU for my two nvidia GPU's, quickly processed them and now seems to be only downloading and processing CPU WU. Nothing has changed in my configuration since earlier today.

Are there different WU sent out by SETI that can only be processed on a CPU or GPU? Or, are all the WU the same and my system can process them on the CPU or the GPU? I can see 10 or so WU that say setiathome_advanced 6.03 just waiting to be processed. When I check my messages it says requesting new tasks for GPU then on the next line got 0 new tasks.

Maybe this is normal but as a newcomer to all of this I don't really know how they handle the WU sent out.

I would obviously rather have the GPU's processing these WU more than my CPU's.

Thanks in advance!


EDIT: I just noticed that it is now crunching on the two GPUs along with the CPU. Can anyone provide me with a link that explains how the WU are distributed? I would like to learn more about how specific WU are handled by the CPU and GPU.

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Message 1033461 - Posted: 17 Sep 2010, 5:33:49 UTC

At the time they are downloaded, they are allocated to the CPU or the GPU. Have you noticed any new CPU units downloaded? You might just be having trouble getting work in general. With the outage this week and the regular outages, that would not be surprising. I believe there is a Rescheduler tool (which I do not use) that someone over at Lunatics (?) made that will allow you to move CPU units to the GPU.

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Message 1033501 - Posted: 17 Sep 2010, 9:40:28 UTC - in response to Message 1033454.
Last modified: 17 Sep 2010, 9:41:33 UTC

There was a server side change made a while ago which means that VLAR tasks that dont run as well on a GPU are only allocated to CPU. You may be experiencing that. Otherwise the MB tasks run on CPU or GPU.

Do your CPU tasks have a name something like xxxxxxxxxxx.vlar_y - those a VLARs which wont get assigned to your GPU.

With a lot of users currently requesting new work you may just have been unlucky and got 0 allocated on that request.

If you have surplus of CPU tasks you could look at Freds Reschedule app which allows you to move tasks from CPU<_> GPU.

Note: The other scheduler app on Lunatics does not work well with Fermi cards.


John.
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Message 1033524 - Posted: 17 Sep 2010, 12:27:49 UTC

BOINC processed about 10 or so more GPU WU last night.

The vlar WU does seem to be just assigned to the CPU. I am seeing more WU waiting to download that say setiathome_enhances6.03 (CUDA). Those are the ones that I saw running on the GPU's last night. It does seem like there are two different WU being dowloaded. Some of the ones waiting to download say setiathome_enhances6.03, the rest say setiathome_enhances6.03 (CUDA). This is why I was asking if SETI has WU specifically designed to run on teh GPU's since it looks like two different things are being downloaded.

If I could I would like to have the GPU's handle everything. It seems like they can chew through a WU in like 20-40 minutes with the CPU taking more like 2-4 hours. (Q6600)

I'll give that app a try.

Thanks for the help.

Adam


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Message 1033537 - Posted: 17 Sep 2010, 13:05:12 UTC

Just out of curiosity, can anyone explain to me why the WU process so much more quickly on the GPU's vs. the CPU? What is it about the architecture of the GPU that makes it so much faster?

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Message 1033544 - Posted: 17 Sep 2010, 13:21:28 UTC - in response to Message 1033537.

Just out of curiosity, can anyone explain to me why the WU process so much more quickly on the GPU's vs. the CPU? What is it about the architecture of the GPU that makes it so much faster?



In simple terms.. The cpu "cores" may be faster, but we have 2 cores, 4 cores, 6 cores..

while most of the video cards have 16 cores up to over 200. this means a lot MORE processors working on the same task. more hands make lighter work, and more cores make faster processing.

The magic that encodes it.. ahh I will leave that to the others. But that is pretty much the readers digest version.
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Message 1033715 - Posted: 17 Sep 2010, 22:04:34 UTC - in response to Message 1033544.

Just out of curiosity, can anyone explain to me why the WU process so much more quickly on the GPU's vs. the CPU? What is it about the architecture of the GPU that makes it so much faster?



In simple terms.. The cpu "cores" may be faster, but we have 2 cores, 4 cores, 6 cores..

while most of the video cards have 16 cores up to over 200. this means a lot MORE processors working on the same task. more hands make lighter work, and more cores make faster processing.

The magic that encodes it.. ahh I will leave that to the others. But that is pretty much the readers digest version.



Ok, that's kind of what I was thinking. I think the 470 has 256 or 350 cores or something, I'm not sure. I remember reading something like that in the specs somewhere. If anyone has a white-paper explaining how SETI breaks up it's WU and how the CPUs and GPUs process them I would be interested in reading it.

Thanks!

Message boards : Number crunching : BOINC not downloading GPU WUs

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