A number of commits to the i965 driver in Mesa today benefit the performance of KDE's KWin window manager for those using Intel Ivy Bridge graphics hardware.
There were a number of commits pertaining to the i965 driver's fragment shared pushed this afternoon (i965/fs
). Most notably, this should help Ivy Bridge with KWin when using the scaling-related effects using the OpenGL 2.x renderer.
The bug report relevant to this Intel IVB OpenGL performance regression is covered at FreeDesktop.org
. There's several commits relevant to this optimization work. One of the commits
by Eric Anholt also mentions a significant performance improvement with one of his GL Shading Language demos.
Like we have done for the VS and for constant-index uniform loads, we use the sampler engine to get caching in front of the L3 to avoid tickling the IVB L3 bug. This is also a bit of a functional change, as we're now loading a vec4 instead of a single dword, though we're not taking advantage of the other 3 components of the vec4 (yet).
With the driver hacked to always take the varying-index path for all uniforms, improves performance of my old GLSL demo by 315% +/- 2% (n=4). This a major fix for some blur shaders in compositors from the varying-index uniforms support I introduced in 9.1.
It also looks like the newly-merged patch series takes care of some Sandy Bridge performance issues too.