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realhet
Miniboss

Recommended way to overlap Ocl kernels on HD7970 Catalyst 12.10

Hi,

I've just downloaded the new driver and noticed, that my program is became 3.7% slower than before. I have figured out that the problem is that the new driver wont allow to execute 2 kernels overlapped.

Here is what worked well before cat 12.10:

start kernel1

at 90% of the exec time of kernel1 -> start kernel2

at 90% of the exec time of kernel2 -> start kernel3

and so on.

(kernel time is around 0.4 seconds)

And the way it was worked on opencl: -> make 2 contexts and run two of the overlapped kernels on each different contexts. Check the completion in a 20msec timer and launch new kernel when needed.

Now this is not working with Catalyst 12.10. It's 3.7% slower now because CUes are sleeping between kernels :S. You know, it's like turning off one of the 32 CUes in a HD7970, just because those bad kernel-to-kernel transitions.

So If anyone knows, please tell what is the proper way to keep the CUes filled with work ALL THE TIME?

Thank you for answers.

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