Created attachment 149033 [details] perf.data SUMMARY Attaching a perf report SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.24.5 KDE Frameworks Version: 5.94.0 Qt Version: 5.15.4 Kernel Version: 5.17.7-zen1-2-zen (64-bit) Graphics Platform: Wayland Processors: 8 × Intel® Core™ i5-8250U CPU @ 1.60GHz Memory: 7,6 GiB of RAM Graphics Processor: Mesa Intel® UHD Graphics 620
perf data is not really transferable between installations, please open it in hotspot on your PC and attach the flamegraph here. It would also be ideal if you could build KWin yourself in RelWithDebInfo mode for recording the data; without debug information there won't be much useful to see.
Created attachment 149162 [details] flamegraph I think it should be this?
I also see high cpu usage with kwin_wayland on my integrated ryzen renoir gpu. It idles between 6-12% which is way higher than kwin_X11.
I discovered the problem is due to Thunderbird (ver. 91.9.1). Firefox isn't a problem, however. Strange.
So when you quit Thunderbird, the high CPU usage goes away? Is Thunderbird running in native Wayland more, or as an XWayland app?
Thunderbird is running native Wayland. The problem goes away when I quit thunderbird.
Are there any animations playing in your Thunderbird window? I notice that kwin_wayland CPU usage spikes whenever anything animates on the screen (w.g. when a notification appears or NeoChat's "someone is typing" indicator appears). But I cannot reproduce that simply having Thunderbird's window open without is doing anything causes kwin_wayland to increase in CPU usage.
No animation is playing and the usage doesn't change whether I minizethr window or not.
FWIW https://bugzilla.mozilla.org/show_bug.cgi?id=1743144#c26
Thanks for the link to the mozilla bug report. CPU usage does indeed drop when running thunderbird in XWayland.
Ok, so I guess this is a known Thunderbird issue. I guess their Wayland support is indeed still experimental. :)