Gamma-ray pulsar search CREDIT

Tex1954
Tex1954
Joined: 15 Mar 11
Posts: 28
Credit: 774270490
RAC: 610858
Topic 197674

Howdy folks,

This GPU task takes much longer than others yet gives the fewest points.

Can we adjust the points up a bit please to sort of match the GPU time involved?

Completed and validated 3,088.53 880.95 9.85 1,000.00 Binary Radio Pulsar Search (Arecibo, GPU) v1.39

Completed and validated 6,104.52 1,935.13 21.63 3,333.00 Binary Radio Pulsar Search (Perseus Arm Survey) v1.39

Completed and validated 7,558.83 7,389.71 82.58 660.00 Gamma-ray pulsar search #3 v1.11

These all on the same GTX-580 setup...

8-)

Gary Roberts
Gary Roberts
Moderator
Joined: 9 Feb 05
Posts: 5872
Credit: 117253145289
RAC: 36216249

Gamma-ray pulsar search CREDIT

Quote:
Can we adjust the points up a bit please to sort of match the GPU time involved?


You mention "GPU time" but none of the figures you quote measure GPU time - it's probably quite minimal for this initial version of the FGRP3 app.

Take a look at this post which announced the start of the FGRP3 run and the provision of a new app for partial use of a suitable GPU. In particular, note the following comment :-

Quote:
As we did with the first BRP GPU apps, so far only the FFT will run on the GPU, the rest of the computation (which is still a lot) is done on the CPU. As the application develops, more and more computation will be shifted to the GPU.


If you look at both elapsed time and CPU time for the example you give, you can appreciate how relatively large the CPU involvement still is - less than 200 secs below the elapsed time. It would probably be fair to call these essentially "CPU tasks with a bit of GPU involvement.

As mentioned, the app will be refined over time to shift as much as possible of the remaining CPU calculations to the GPU. When that is done, I would expect both CPU time and elapsed time to decrease dramatically. As was done with BRP apps when they matured, you may even see multiple tasks being combined into one large task with appropriate increase in the awarded credit. At that point you could make a much better assessment of the fairness or otherwise of the credit allocation.

Cheers,
Gary.

Tex1954
Tex1954
Joined: 15 Mar 11
Posts: 28
Credit: 774270490
RAC: 610858

Well, I didn't pay much

Well, I didn't pay much attention to the CPU time as the GPU time still looked like a lot..

But, what you say makes sense.

Thanks!

8-)

Gary Roberts
Gary Roberts
Moderator
Joined: 9 Feb 05
Posts: 5872
Credit: 117253145289
RAC: 36216249

RE: Thanks! You're

Quote:
Thanks!


You're welcome!

I should have made it clearer that the first mentioned time (elapsed time) is not a good measure of GPU involvement as the GPU is idle for those periods when waiting for CPU stuff to be done. You can see this by looking at GPU load which is quite low a lot of the time and spikes upward when the GPU is actually doing some work.

For the more efficient BRP apps, GPU load is more uniformly high so the elapsed time is a better measure of the GPU involvement.

Cheers,
Gary.

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