On 03/23/2018 11:39 AM, Matt Turner wrote: > On Wed, Mar 21, 2018 at 5:58 PM, Ian Romanick <i...@freedesktop.org> wrote: >> From: Ian Romanick <ian.d.roman...@intel.com> >> >> Now that i965 recognizes that a-b generates the same conditions as 'a < >> b', there is no reason to condition this transformation on 'is not used >> by conditional.' >> >> Since this was the only user of the is_not_used_by_conditional function, >> delete it. >> >> All Gen6+ platforms had similar results. (Skylake shown) >> total instructions in shared programs: 14400775 -> 14400595 (<.01%) >> instructions in affected programs: 36712 -> 36532 (-0.49%) >> helped: 182 >> HURT: 26 > > Looked at why these are hurt? :)
I should have known you were going to ask that. :) Since the changes were small, I tried to avoid looking at them so that I wouldn't get distracted again. But since you asked... Shaders from 4 apps were hurt. All but one of the hurt sharders was an ARB_fragment_program. I looked at a shader from each of the four apps, and in all of those cases a ffma / compare with zero became a multiply / compare with something else. We already have a general case of this transformation in last optimizations. So, I tried making this transformation more general (by removing the fneg) and added a transformation to strip the fnegs from -a < -b. The results on SKL are below. I'm not excited about the "max: 27 x̄: 2.26". I think I'd like to land this patch as-is. I'm also going to play with moving all the comparison munging out of late optimizations. I have some patches in the queue that add some more transformations, so it will be interesting to see the effect of moving them earlier. total instructions in shared programs: 14400775 -> 14399973 (<.01%) instructions in affected programs: 242118 -> 241316 (-0.33%) helped: 1298 HURT: 325 helped stats (abs) min: 1 max: 7 x̄: 1.18 x̃: 1 helped stats (rel) min: 0.11% max: 9.09% x̄: 1.73% x̃: 1.16% HURT stats (abs) min: 1 max: 27 x̄: 2.26 x̃: 1 HURT stats (rel) min: 0.14% max: 5.26% x̄: 0.79% x̃: 0.43% 95% mean confidence interval for instructions value: -0.61 -0.38 95% mean confidence interval for instructions %-change: -1.32% -1.14% Instructions are helped. total cycles in shared programs: 532929592 -> 532919072 (<.01%) cycles in affected programs: 3525194 -> 3514674 (-0.30%) helped: 1896 HURT: 608 helped stats (abs) min: 1 max: 714 x̄: 14.12 x̃: 4 helped stats (rel) min: 0.03% max: 26.92% x̄: 1.10% x̃: 0.68% HURT stats (abs) min: 1 max: 281 x̄: 26.72 x̃: 8 HURT stats (rel) min: 0.01% max: 40.94% x̄: 2.19% x̃: 0.95% 95% mean confidence interval for cycles value: -5.88 -2.53 95% mean confidence interval for cycles %-change: -0.41% -0.19% _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
