Comment # 6 on bug 92996 from Ernst Sjöstrand

I don't even get 60 fps in glxgears with a tiny window:
292 frames in 5.0 seconds = 58.264 FPS
286 frames in 5.0 seconds = 57.198 FPS
291 frames in 5.0 seconds = 58.198 FPS
(amdgpu ddx+dri2)