https://bugs.freedesktop.org/show_bug.cgi?id=43000
--- Comment #3 from Ian Romanick idr@freedesktop.org 2011-11-16 14:25:23 PST --- If this was a recent change, I'll guess that it will bisect to my changes to the way uniforms are handled. I pushed a patch today that may restore previous performance:
commit 010dc29283cfc7791a29ba8a0570d8f7f9edef05 Author: Ian Romanick ian.d.romanick@intel.com Date: Thu Nov 10 12:32:35 2011 -0800
mesa: Only update sampler uniforms that are used by the shader stage
Previously a vertex shader that used no samplers would get updated (by calling the driver's ProgramStringNotify) when a sampler in the fragment shader was updated. This was discovered while investigating some spurious code generation for shaders in Cogs. The behavior in Cogs is especially pessimal because it ping-pongs sampler uniform settings:
glUniform1i(sampler1, 0); glUniform1i(sampler2, 1); draw(); glUniform1i(sampler1, 1); glUniform1i(sampler2, 0); draw(); glUniform1i(sampler1, 0); glUniform1i(sampler2, 1); draw(); // etc.
ProgramStringNotify is still too big of a hammer. Applications like Cogs will still defeat the shader cache. A lighter-weight mechanism that can work with the shader cache is needed. However, this patch at least restores the previous behavior.
Signed-off-by: Ian Romanick ian.d.romanick@intel.com Reviewed-by: Kenneth Graunke kenneth@whitecape.org