Critical performance regression on 4.16.x
This video shows the difference in performance between current 4.16.1 and 4.14.2. I'm using ScreenStudio window to show the drawing performance only because it's a heavy window and it's more evident, but you can easily see the difference in any window. And it's not just resizing or moving, but all drawing events are clearly slower.
https://www.youtube.com/watch?v=qeBlBBXXJAo
Observations:
.All settings are Xfce default, including compositor ON.
.If I disable compositor (not shown in the video), things get even crazier and it reminds me when we finished Solitary game in Windows :P
.Video card: Nvidia GTX 650 Ti using nouveau driver (but it doesn't matter if I use the official driver; I tested it)
.Distro: Porteus 5 RC2 x64 (I'm one of the developers), which uses Slackware packages
.Built with the following flags: http://ftp.slackware.com/pub/slackware/slackware64-current/source/xfce/xfwm4/xfwm4.SlackBuild
.A friend of mine using another machine with Intel Graphics couldn't replicate the issue, however another friend of mine with a similar Nvidia card reported the same bad performance I have. Apart from the hardware, both of them are using the same system.
.EDIT: my machine happens to have an Intel Graphics card so I removed my Nvidia card and tested everything again on Intel and the result is the same.
.EDIT2: I could replicate in VirtualBox the issue on nightly Xubuntu (from 7th January 2021) which uses Xfce 4.16. Testing on Xubuntu 18.04 (Xfce 4.12) the issue doesn't occur.