Matt Turner <matts...@gmail.com> writes: > On Mon, Feb 16, 2015 at 10:40 AM, Francisco Jerez <curroje...@riseup.net> > wrote: >> My intuition is that the huge performance improvement Matt observed by >> disabling the third scheduling heuristic is more likely to have been >> caused by a decrease in the amount of cache thrashing caused by the fact >> that he was running less channels concurrently rather than by the >> scheduling heuristic itself. Matt, did you rule out that possibility? > > Actually, the fragment shader used in the demo [1] doesn't can't > register allocate in SIMD16 at all. > > From my Dec/Jan status report: > >> As an aside, I did an experiment to see what would happen if we used >> SCHEDULE_PRE and spilled anyway (I added a couple of extra instructions >> to increase register pressure over the threshold). I changed the window >> size to 2048x2048 and rendered 1000 frames. >> >> SCHEDULE_PRE with no spills: 17.5 seconds to render 1000 fames >> SCHEDULE_PRE with 4 spills (8 sends): 17.5 seconds >> SCHEDULE_PRE_NON_LIFO with no spills: 28 seconds > > The demo does no texturing (no send instructions at all if no > spilling), so it's not affected by caching as far as I understand. > > [1] https://github.com/ashima/webgl-noise
Ahh, yes, that makes sense to me too.
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