Has anyone noticed severe performance regression since X Server 1.18?

[Adam Jackson]

On Tue, 2018-04-17 at 19:53 +0200, Kevin Brace wrote:

> When EXA is in use, the performance is roughly something like Version
> 1.11 > Version 1.15 > Version 1.18 / 1.19.

Surely a profile would show different results between these points.
There's something like 2000 commits between 1.15 and 1.18, I'm not sure
I could guess which one might be your culprit without a little more
detail than "something got slow". But since I can't help myself...

As you're not accelerated you're probably using shadowfb. There's been
basically only one major change there since 1.15:

https://cgit.freedesktop.org/xorg/xserver/commit/?id=2dcb1672620ef5f16111517e9e7a98cf97deb678

I would be somewhat surprised if that turned out to be the guilty
commit, as the damage code has to do all the same work, but it's
possible the old CopyWindow hook was a real win.

- ajax