https://bugs.freedesktop.org/show_bug.cgi?id=96790
--- Comment #11 from Michel Dänzer michel@daenzer.net --- So it looks like the drops are due to shader compilations. Given that you're using current LLVM SVN & Mesa Git, that should only happen if the application explicitly asks to compile new shaders. Marek pushed changes to Mesa Git master this week which might help somewhat, otherwise a persistent shader cache may be the only hope.