(In reply to Jan Ziak from comment #9)
> Created attachment 124063 [details]
> kcachegrind screenshot: _mesa_FenceSync
> 
> I ran callgrind on Bioshock with mesa-git.
> 
> Callgrind instrumentation was enabled only when the Bioshock benchmark was
> rendering frames from the game. The benchmark graphics quality was set to
> Medium.
> 
> The screenshot I am sending indicates that Bioshock expects a faster
> _mesa_FenceSync implementation.

I wouldn't trust callgrind, because it runs on a CPU emulator.

The proper way to profile this is to build Mesa with -fno-omit-frame-pointer
and use sysprof, which is very easy to use. Sysprof can also save the results
to disk.