Around the place where the the webgl examples show up performance tanks.

clip shaders:
https://share.firefox.dev/39GEStH

Seems like we spend an unreasonable amount of time in cs_clip_rectangle_FAST_PATH and we may need some sort of actual swgl fast-path here to deal with it if it proves enough of an issue.

It seems like there might be something a bit mac specific here. Both Jimb and I weren't able to reproduce a similar profile in Linux.

(In reply to Jeff Muizelaar [:jrmuizel] from comment #2)

It seems like there might be something a bit mac specific here. Both Jimb and I weren't able to reproduce a similar profile in Linux.

I tried on Linux as well, at high res and scale, and it didn't seem to result in what was shown in the report profile either.

So it is quite possible there is something related to how we attach external images for WebGL with Mac.

About the only remaining overhead here of great note is the fast that the background here really stressed the linear repeat filtering path. Maybe we can try to do better eventually, which is tracked in bug 1678783.

Bug 1678783 should have helped with the linear repeat overhead on this page.