https://bugs.freedesktop.org/show_bug.cgi?id=82055
--- Comment #14 from Michel Dänzer michel@daenzer.net --- (In reply to comment #13)
According to the sysprof output, libpixman is the place where moste CPU time goes.
That just means the problem is a software rendering fallback path, but it doesn't show which one. You'd need to make sure at least the X server binaries are compiled with -fno-omit-frame-pointer and have debugging symbols.
(In reply to comment #7)
Do you know which commit resolves this?
Not sure, but my guess would be http://cgit.freedesktop.org/xorg/xserver/commit/?id=45ebc4e3fac7f1a85167d05e... or one of the commits surrounding it.
If not, do you need a bisect?
That would be interesting.
If yes, will that commit be backported to the 1.16 branch?
I can't predict the future, you'll have to nominate it and see. :)