[Intel-gfx] FireFox performance regressions XAA -> EXA -> UXA

[Clemens Eisserer]

Hi Chris,

Thanks for taking the time.

@Chris: With XAA, is rendering really done client-side by firefox?
I thought with XAA, xorg simply calls pixman for almost everything,
but its still server-side?

What I wonder is why the old EXA version does so much better.
During many regressed tests I see quite some time spent in
kernel-code, does GEM add so much overhead?
Wasn't GEM introduced to make everything faster? For 2D I see heavy
regressions, and OpenGL games still perform a lot worse compared to
Intel's windows drivers. (I can play tuxracer with everything set to
high on windows, on Linux I have to reduce resolution and visibile to
make it playable).

> However, those results are quite sobering and hopefully we will be able to
> use them to gain some meaningful insight into the vexed question of why
> firefox does indeed feel so slow. Now all I have to track down this
> mysterious script and reproduce those numbers...

Carl has the script uploaded here: http://cworth.org/trender_bookmark/
I have no idea how accurate the measurements are (however it repaints
long enough to compensate for missing flushing), but the orders of
magnitues at least show a "tendency".

- Clemens

PS: And the worst: Firefox on Windows-XP feels faster on all of those
benchmarks. Scrolling my GMail-Inbox was no problem at all, even on
way slower machines.