The patch that was authored by Intel's Zou Nan hai and committed by Kenneth Graunke is rather simple. The patch just increases the maximum WM thread count to 80 from 40 for "Gen6 GT2" graphics, a.k.a. Intel Sandy Bridge processors with the HD 3000 graphics.
Previous to increasing the WM thread count limit there was a code comment that the number could potentially be increased but would require disabling of WIZ hashing and resetting the GPU. It turns out that those changes aren't actually needed and that the WM thread count can be upped to 80 without changing anything else. This simple change now ups the Counter-Strike: Source frame-rate by 7.18% based upon the Git commit.
intel: increase wm thread number to 80 on gen6 GT2It wasn't reported what other OpenGL workloads this Intel Mesa DRI driver commit (to be included in Mesa 8.1) will benefit or by how much, but of course Phoronix benchmarks will illustrate that next time around.
It seems reset is not required for setting the max_wm_threads to 80 on gen6 GT2. Increases performance in the Counter-Strike: Source video stress test by 7.18% (n=5).
Good times are ahead for Valve's games on Linux.