[Mesa-dev] [PATCH] ra: Disable round-robin strategy for optimistically colorable nodes.

Matt Turner mattst88 at gmail.com
Mon Feb 16 10:51:06 PST 2015

On Mon, Feb 16, 2015 at 10:40 AM, Francisco Jerez <currojerez at 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

More information about the mesa-dev mailing list