Task taking 1 CPU plus 1 GPU ?
24 Jan 2010 17:24:33 UTC
Topic 194746
(moderation:
I've got a quad-core Phenom box with a 9600 GT and a 9600 GSO.
Yesterday I was scratching my head trying to figure out why it was only running four tasks (that is, two CPU and two GPU) when it should have been running four CPU and two GPU.
I figured out what was happening -- it was running two Einstein@home tasks and those two tasks were both using 1 CPU core and 1 nVidia GPU at the same time! BOINC even said "1.00 CPUs plus 1.00 NVIDIA GPUs" for each task.
Any idea why that was happening? I suspended each task, but then BOINC started running two more Einstein tasks doing the same thing. I had to reset the Einstein@home project to get it to behave.
I thought Einstein couldn't even use CUDA...
Task taking 1 CPU plus 1 GPU ?
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For info on Einstein CUDA applications, see this sticky thread.
BTW, the so called ABP2 application is supposed to use one CPU && one GPU.
Michael
Team Linux Users Everywhere
RE: I've got a quad-core
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You diagnosed the situation correctly.
The current E@H GPU app still runs mostly on the CPU, and only uses the GPU a little bit. So, it ties up a whole CPU core AND your whole GPU. Although the GPU app runs faster than the CPU-only app, it doesn't run a whole lot faster.
If you have other projects you can run on your GPU, you're probably better off not running E@H GPU apps yet -- IMHO they're very immature at this point and a waste of GPU resources. If you're not running anything else on your GPU, then it doesn't hurt. It will (in most cases) run faster than the CPU-only application. (Although, if you have a fast CPU and slow GPU, some people have reported that the GPU app runs *slower* than the CPU app. YMMV)
Want to find one of the largest known primes? Try PrimeGrid. Or help cure disease at WCG.
RE: You diagnosed the
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Is there a way I can configure Einstein to use only the CPU, yet allow other projects to use the GPU if they wish?
RE: For info on Einstein
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Ah, after reading that thread it makes sense. Unfortunately it seemed to be running extremely slowly on my 9600, and I'd prefer to use the GPU for another project. I think when my GTX 260 arrives I'll give ABP2 another shot.
RE: Is there a way I can
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Sure, go to the E@H project preferences http://einstein.phys.uwm.edu/prefs.php?subset=project and deselect the option to use GPU.
The setting will be synced to your PCS when doing the next server communication (can be forced by pushing "update" in BOINC manager).
This will disable GPU for Einstein@Home on all your hosts. If you rather want to disable GPU only for selected hosts, you con assign those hosts to a special venue you do not use (say, "school") and disble GPU processing only for this venue. The venue can be selected on the page showing your host details.
Cheers
HB
RE: Sure, go to the E@H
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Great! Thanks for the tip.
RE: RE: Sure, go to the
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You're welcome! But be warned, you might find out that the ABP2 tasks run quite a bit slower on your AMD quad-core CPU. The difference between GPU and CPU task runtime actually in general seems to be much larger for AMD CPUs: the Intel Core2s seem to do a far better job computing the FFTs in ABP2, which is the part that is done on the GPU in the CUDA app. I would not be surprised if the GPU app were faster on your PC by a factor of 1.7 to 1.9. That seems to be about the ratio for my AMD 4850e PCs
CPU : 5700 sec 5.7k sec
GPU (9800 GT "Eco") : 3k sec
Factor: 1.9 (almost twice as fast, and this isn't even a very fast CUDA card). A factor of 2 is probably the upper limit of the speed-up that you can expect.
It will be intersting to see the comparison for your AMD quadcore.
CU
HB
RE: You're welcome! But be
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I stuck with AMD for years since the price/performance ratio was so much better than Intel, but lately I'm finding going with AMD really puts you behind the game as compared to those crunching with Intel chips, especially Core i7s. The SETI guys swear by Intel -- the only computers in the top 20 or so with AMD chips also have four or five GTX 295s. :)
I'll give this some thought. I need to come up with an overall strategy for which DC projects are going to run best on my half-dozen boxes, and maybe detach some.
RE: The SETI guys swear by
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You'll find the same Intel dominance here at E@H, it's a bit sad :-( .
CU
HB
RE: You'll find the same
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Yup. For years it was cool and smart to be in the AMD camp -- their chips were faster, cheaper, and drew less power (which is super important for laptops.)
It took a while, but the empire finally struck back with the Core2 chips, which were markedly faster and significantly lower in power consumption than their AMD equivalents. Intel was still more expensive, but at least you were getting more bang for your buck.
The Core i7 is continuing where the Core2 left off. AMD has its work cut out for it; they are definitely behind the curve with respect to CPUs.
Want to find one of the largest known primes? Try PrimeGrid. Or help cure disease at WCG.