GPU performance significantly slow when running multiple MATLAB
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Hi:
I have a code using GPU calculation, when it used by 1 MATLAB, it runs OK.
but when I open two MATLAB.exe in my computer, and run this GPU-relate function at the same time, the GPU performance becomes significantly slow.
for example, when run 1 MATLAB, it cost about 20 seconds, but when 2 MATLAB runs at the same time, it cost about 2000 seconds.
one thing I'm sure is that the GPU memory is enough for more than two tasks. therefore, the memory should not be the problem.
my GPU is GTX 980ti, which has 6GB memory.
Just want know if there is any mistake with my operation, or is there anyway to improve this performance.
Thanks!
Yu
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Answers (1)
Joss Knight
on 20 Sep 2018
Edited: Joss Knight
on 20 Sep 2018
I'd be very surprised if memory isn't the issue here, because contention between your two MATLABs will be forcing continual synchronization and raw allocation on both. I'd have to see what it is you're doing.
Ultimately you should explain why you are using two MATLABs if you only have one GPU. You may have a good reason of course but it's worth looking into.
10 Comments
Walter Roberson
on 22 Sep 2018
"Just want know if there is any mistake with my operation"
Yes, it is a mistake to share the GPU between multiple processes in Windows.
A document I was examining recently on how NVIDIA GPU handle multiple processing indicated that task synchronization is expensive in relative terms, and that moving tasks on / off of the GPU is the most expensive operation for their GPU.
When you run two different processes each trying to access the GPU, you are forcing it to run the most expensive operation often.
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