<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - 6% performance drop in GpuTest v0.7 Volplosion with "remove GLSL IR optimisation loop"" href="https://bugs.freedesktop.org/show_bug.cgi?id=100913#c5">Comment # 5</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - 6% performance drop in GpuTest v0.7 Volplosion with "remove GLSL IR optimisation loop"" href="https://bugs.freedesktop.org/show_bug.cgi?id=100913">bug 100913</a> from <a class="email" href="mailto:t_arceri@yahoo.com.au" title="Timothy Arceri <t_arceri@yahoo.com.au>"> Timothy Arceri</a> <pre>(In reply to Matt Turner from <a href="show_bug.cgi?id=100913#c2">comment #2</a>) > Looks like this regression could/should have been caught by shader-db: > > LOST: shaders/closed/gputest/volplosion/7.shader_test FS SIMD16 > > > Separately, Curro is having an interesting time with this particular shader > with his new scheduler. Perhaps if that is sorted out, the regression will > be fixed. Right. As Ken said there were differences noticed, but it would be pretty difficult to not see any difference considering the change. The results from BDW as per the commit message were: LOST: 17 GAINED: 40 Looking at the output the only real difference I can see is the ordering of the final nir instructions which seems makes a big diff to the scheduler. It appears when the vectors are split in nir the instructions seem to be grouped together as per the execution order of the vectors in the shader, in contrast the GLSL IR the instructions seem to be order such that they are grouped slightly more towards executing more instructions on a channel one after the other. This is probably enough to free up some registers. I suspect the only thing we can do is wait for Curros new scheduler. We could revert the change, but that just feels like it hides the problem rather than fixes it and would be a step backwards IMO.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>