https://bugs.kde.org/show_bug.cgi?id=478915
Bug ID: 478915 Summary: Continuous CPU load after X11 login Classification: Plasma Product: kwin Version: 5.91.0 Platform: Other OS: Linux Status: REPORTED Severity: normal Priority: NOR Component: general Assignee: kwin-bugs-n...@kde.org Reporter: jpe...@petsovits.com Target Milestone: --- Created attachment 164388 --> https://bugs.kde.org/attachment.cgi?id=164388&action=edit Flamegraph SVG of kwin_x11 at a constant but not debilitating load SUMMARY Logged into my Plasma 6.0 Beta dev session (built two days after Beta 2) and the fans started spinning. On an 8-core Intel Core i7-8565U, ThinkPad X1 Carbon Gen 7 laptop with iGPU, ksysguard showed a constant 13%-14% of CPU usage for kwin_x11 and 4%-5% for picom. So it didn't quite incapacitate the system, and cursor overlays were fluid but window moves were at an estimated <5 FPS. I don't have a full stacktrace, but I used https://github.com/flamegraph-rs/flamegraph to capture a few seconds of constant load and generate a flamegraph SVG. Find the SVG attached. It looks like debuginfod was not used because the system-level libraries don't show function-level info. Sorry. I figure the actual perf.data output is also not useful outside of my system, but I have it sitting here for a few days until I rebuild kwin again sometime. STEPS TO REPRODUCE 1. Log into a KF6 X11 session. 2. Get lucky, notice high system load. 3. ??? 4. `perf` it! SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.91.90 KDE Frameworks Version: 5.248.0 Qt Version: 6.6.1 Kernel Version: 6.6.3-arch1-1 (64-bit) Graphics Platform: X11 Processors: 8 × Intel® Core™ i7-8565U CPU @ 1.80GHz Memory: 15.3 GiB of RAM Graphics Processor: Mesa Intel® UHD Graphics 620 Manufacturer: LENOVO Product Name: 20QD001VUS System Version: ThinkPad X1 Carbon 7th ADDITIONAL INFORMATION * The session I had previously logged into was a Plasma 5.27.9 session on X11. (Picked the wrong X11 SDDM entry because usually this user account is reserved for Plasma 6 only.) * Upon logout from the CPU-intensive KF6 X11 session, SDDM did not come back and the screen stayed black. Probably unrelated as it also happened after the next session. * Following a hard reboot, I logged into the same KF6/X11 Plasma session again to see if the issue is always reproducible. It is not, CPU load was nice and low now. -- You are receiving this mail because: You are watching all bug changes.