Forum > GPU crunching
What is good settings for my ATI R5770?
Raistmer:
Yes, if GPU processing few heavely blanked tasks there can be GPU usage drop even with few tasks per card.
But I think there is the way to distinguish such pattern from GPU low usage bug pattern.
Heavely blanked pattern should have almost 100% spikes when FFA done on GPU (it's best optimized partion IMHO cause I worked on it from Brook+ times). Blanking affects on processing between FFAs and FFA itself should make use of almost all GPU.
Whereas low usage bug pattern will shouw steady low % perhaps.
Not sure in that but you can make observations and improve my suggestion.
Mike:
Did that already.
On AP using r558 GPU usage bouncing between 20% and 45% running 2 instances.
On high blanking its bouncing as well so you only can try with suspend and resume.
My times varies between 3000 secs and 10000 secs with blanking less than 15%.
Additional note:
While on MBs suspending work cures at least for whole unit in progress, on APs low GPU load returns after a few minutes sometimes.
I imagine it depends on steadily CPU usage ?
Raistmer:
WoW, good observation!
No, I think not.
There is key difference in buffer allocations for MB and AP.
While MB does more or less homogenic calculations AP implements 2 almost independent sections - main loop and FFA.
For FFA we need different buffers (different number, different sizes) than for main loop single pulse search.
Hence there is only once buffers allocation in MB, at the beginning, but constant buffers recreation/discarding for AP.
Before there was opinion that low GPU usage bug can be connected with orphaned OpenCL resources left behind when task finished. Indeed, I did not directly deallocate buffers in MB leaving cleanup for OS/OpenCL runtime (as should be when OS process get killed).
But I do buffers deallocation in AstroPulse ! When transition from main loop to FFA occurs some of main loop buffers are deallocated and FFA ones are allocated, and vice versa. So, the problem not in deallocation, the problem in allocation!
No clue how to fix it on our end still, but at least it's good bug report to AMD.
Claggy:
This is the sort of load i get with ATI AP when there is minimal load:
and this is what it like once i've suspended and resumed the Wu (notice the higher frequency of memory usage):
Claggy
KarVi:
That is exactly what it looks like on mine as well.
I must note that I hadn't noticed the error before optimizing the settings.
I'm thinking about going back to see if it disappears with the standard settings...
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