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Message boards : Graphics cards (GPUs) : 3 GPU's, # of expected WU's?

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Message 5113 - Posted: 31 Dec 2008 | 13:34:20 UTC

I have had two 8800GT's crunching for about 3.5 months. That always downloads 4 WU's -- 2 that crunch immediately and 2 in waiting. Given our recent work issues, I figured I throw in a 9500GT (factory OC'd) that I had laying around, expecting to get 6 WU's. The 9500GT is slow, but can finish 1 WU with plenty of time before the deadline and the 2nd WU would get crunched by one of the 8800GT's. However, after getting the 9500GT in the system, it crunches 3 WU's but only has 1 in reserve (same # of WU's before the 9500GT).

It definitely identified the 3 CUDA devices:
12/31/08 00:37:06||CUDA devices: GeForce 8800 GT, GeForce 8800 GT, GeForce 9500 GT


It is also definitely trying to get more work every few minutes, but running into the message that I am already saturated with WU's. Any ideas?

12/31/08 07:47:14|GPUGRID|Sending scheduler request: To fetch work. Requesting 130899 seconds of work, reporting 0 completed tasks
12/31/08 07:47:19|GPUGRID|Scheduler request completed: got 0 new tasks
12/31/08 07:47:19|GPUGRID|Message from server: No work sent
12/31/08 07:47:19|GPUGRID|Message from server: (reached per-CPU limit of 1 tasks)

...

12/31/08 08:23:32|GPUGRID|Sending scheduler request: To fetch work. Requesting 130899 seconds of work, reporting 0 completed tasks
12/31/08 08:23:37|GPUGRID|Scheduler request completed: got 0 new tasks
12/31/08 08:23:37|GPUGRID|Message from server: No work sent
12/31/08 08:23:37|GPUGRID|Message from server: (reached per-CPU limit of 1 tasks)

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Message 5114 - Posted: 31 Dec 2008 | 13:48:01 UTC

Taking a closer look at the server message, I see it specifically says "per-CPU limit". I have a Q6600, so that must be where the 4 tasks for 4 CPU's comes from. However, given I can crunch 3 at a time now, can this limit be raised to 2? That will let a Q6600 download 8 WU's, which even with just 2 8800GT's I can crunch in a little under 3 days.

This might also help others with speedier cards like 2xx series that can crunch 4 WU's / day. I'd expected a Q6600 with a 2xx card to download a max of 4 WU's at a time, which is only 1 day's worth. With the per-cpu limit at 2, the 2xx's would have 2 days worth of WU's available at all times.

Ideally, this would be tied to the # of graphics cards, not the number of CPU's. But, I understand GPU-processing is in its infancy and I can't expect the world. However, the suggestion above for a 2 WU per cpu limit might relieve a lot of WU issues we are currently experiencing.

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Message 5143 - Posted: 1 Jan 2009 | 16:16:37 UTC

I think the idea was to go straight to a per-GPU limit. The main problem with increasing the per-CPU limit is that the BOINC work fetch (in the 6.4.x clients) and the estimated WU completion times are still screwed. BOINC downloads too much work on slower cards, which has to be aborted by the user.. this only gets worse if more work per CPU is allowed.

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Message 5148 - Posted: 1 Jan 2009 | 16:48:33 UTC - in response to Message 5143.

I think the idea was to go straight to a per-GPU limit. The main problem with increasing the per-CPU limit is that the BOINC work fetch (in the 6.4.x clients) and the estimated WU completion times are still screwed. BOINC downloads too much work on slower cards, which has to be aborted by the user.. this only gets worse if more work per CPU is allowed.

MrS

Don't forget that there are also issues with the "work Fetch" policy and Resource Share model used by BOINC. Dr. Anderson put out a proposal to change this. There has been some comments on this proposal and I made a RTF with the changes (discussed in another thread on this board) which we pretty universally received with silence (to date).

Anyway ...

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Message 5153 - Posted: 1 Jan 2009 | 17:24:30 UTC

True. Ideally it will be tied to # of GPU's and be able to determine the estimated time for a particular GPU. That's a wish that isn't probably that close to being fulfilled.

I have been able to babysit the work -- sometimes I still get the "not available" message, but I generally have been able to keep all three GPU's crunching. If the fetch issues (and 24 hour connection delay) are fixed, I think I will been fine. I can keep an eye on it until that day comes.

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Message 5159 - Posted: 1 Jan 2009 | 21:53:48 UTC - in response to Message 5153.

True. Ideally it will be tied to # of GPU's and be able to determine the estimated time for a particular GPU. That's a wish that isn't probably that close to being fulfilled.

I have been able to babysit the work -- sometimes I still get the "not available" message, but I generally have been able to keep all three GPU's crunching. If the fetch issues (and 24 hour connection delay) are fixed, I think I will been fine. I can keep an eye on it until that day comes.


Well, it is more than just fetching the work ... though that seems to be the only problem that Dr. Anderson is willing to address ... if you look at the changes to the proposal he has actually backed down on the scope of the change and what will be addressed. If you look at the mailing list you can see that I am not the only one concerned that by such narrow focus we are not only losing an oppertunity to address several other significant issues but to also set the stage for project to come ...

Just as an illustrative example, let us say that you were silly enough to want to do work for SaH ... and you want to allow them to use 40% of your CPU, but though you did not mind them using part of your GPUs, you only want them to use 20% ... there is no way currently to address this ... other than some real esoteric maneuvers on your part involving multiple computers ...

And this is partly what I have been unsuccessfully trying to get Dr.Anderson to acknowledge ... and to work on ...

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Message boards : Graphics cards (GPUs) : 3 GPU's, # of expected WU's?

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