[regression] performance drop on Dota 2, CS:GO, and gfxbench GL benchmarks on ICL/Iris
A perf drop of ~5-10% was detected in the Intel perf CI on many GL games/benchmarks tested there (Dota 2, CS:GO, and gfxbench GL benchmarks), on ICL with Iris driver. @majanes was attempting to reproduce this on his ICL laptop but was unable to. I didn't have any trouble reproducing it on an ICL from the CI, so perhaps this regression only affects certain configurations of ICL?
commit 878c770d13df355432da053c015b7701b3c533e1 (refs/bisect/bad) Author: Francisco Jerez <email@example.com> Date: Wed Feb 5 18:58:23 2020 -0800 iris: Insert buffer barrier in existing cache flush helpers. As a first step to phasing out the current hashtable-based depth and render cache tracking mechanisms. Reviewed-by: Kenneth Graunke <firstname.lastname@example.org> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3875>
That commit is part of a series, but the perf drop can still be seen on mesa master as of today.