| Summary: | Extreme Kwin Compositor on Wayland CPU Usage on Idle | ||
|---|---|---|---|
| Product: | [Plasma] kwin | Reporter: | Jack <idontlikebugs> |
| Component: | performance | Assignee: | KWin default assignee <kwin-bugs-null> |
| Status: | RESOLVED WORKSFORME | ||
| Severity: | major | ||
| Priority: | NOR | ||
| Version First Reported In: | 6.3.5 | ||
| Target Milestone: | --- | ||
| Platform: | Arch Linux | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed/Implemented In: | ||
| Sentry Crash Report: | |||
| Attachments: | Kwin Extreme CPU Usage On Both: X11 and Wayland Screenshots + Info | ||
Can you attach hotspot (a KDAB project) to kwin_wayland to see where it spends most of its cpu cycles? Also are you building plasma packages yourself? i.e. where does "local/" prefix come from? 🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME. For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging. Thank you for helping us make KDE software even better for everyone! 🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME. |
Created attachment 181650 [details] Kwin Extreme CPU Usage On Both: X11 and Wayland Screenshots + Info ## What I did ## Giving the fact that Plasma started to be unusable for x11 (kwin regression and high CPU usage on X11), I tried and loaded the session with Wayland. Doing almost absolutely nothing triggered the HIGH CPU usage. ## Steps to reproduce ## 1. Load session with Wayland 2. Open Konsole (btw, not sure if the default compilation has 'ctr+alt+t" ready, but if NOT, please fix it; it's as common as ctr+c/v). 3. Type "top" 4. Open Firefox/Librewolf/Zen/Waterfox/Mull/Floorp etc. Don't load any page. Let it idle. (FYI: My Firefox is tweaked/hacked to have ZERO connections on startup, and for quite some time Firefox has been defaulting to wayland, so it's NOT running via xwayland). 5. Return to 3. Observe results. 6. On the other hand, same steps as above, on X11, don't trigger HIGH CPU usage. [Before someone starts to blame something else besides broken Kwin here is some stuff:] ## Additional Info (that has nothing to do with the bug) ## 1. There is nothing in my /etc/environment variables (only my previous, already hashed stuff when I had tried vulkan- worked OK, btw.) 2. There is nothing suspicious in Firefox settings, I even tried some variables (e.g. turning off widget.wayland.vsync.enabled, turning off widget.wayland.opaque-region.enabled etc. There's no fractional scaling on my system either. Kwin CPU usage on Wayland still sucks.) 3. I even tried turning mitigations off and regenerated GRUB (yes, I use GRUB, not systemd-boot). Nope. Kwin still sucks. As you can see the only blame is Kwin Wayland code. The same steps do not trigger this bug on X11 (apart from the huge regression bug on X11). ## Expected results ## By fixing Kwin CPU behavior, return to the state of usability of Plasma, to the working state as it was on KDE 5 (X11). In current state KDE Plasma is unusable. Fix Kwin and free the CPU for user's applications. ## Final Thoughts ## This is a very serious issue. More important than adding new "features", nobody has asked for. After all these years of Plasma coding, it is still not ready at all, where it can be usable as a daily driver with wayland (and now it regressed even on X11). CPU usage, even on idle, sucks. See both screenshots. At this point GNOME 48.1 gives more CPU for user's applications (much quieter, cooler laptop, longer battery life, longer video playback on battery, finishing video/photo encoding first, longer Internet browsing time while traveling, faster databases searches, faster page loads exactly the same browser, more fps for games, better multitasking etc.). ## Some libraries (Arch, pacman -Syyu on 22.05.2025) ## local/kwin 6.3.5-1 (plasma) local/kwayland 6.3.5-1 local/kwayland-integration 6.3.5-1 local/qt6-wayland 6.9.0-2 (qt6) local/wayland 1.23.1-2 local/mesa 1:25.1.1-1 local/intel-gmmlib 22.7.1-1 local/intel-media-driver 25.2.1-1 ## Kinfo ## Operating System: Arch KDE Plasma Version: 6.3.5 KDE Frameworks Version: 6.14.0 Qt Version: 6.9.0 Graphics Platform: Wayland Processors: Intel Graphics Processor: Intel HD Graphics