Plasma 6.2 very poor performance with llvmpipe compared to 6.1

Help
1

My work laptop (Lenovo w/Ryzen 4700U and igpu) has some kind of hardware issue that it resets unless nomodeset is on. I’ve been using it like that for several years and it is slower but still worked fine.

With the recent update to Plasma 6.2 (still on 22.04) the performance has drastically dropped. It is now very laggy while scrolling, moving the mouse, or doing anything really.

Edit: I found the fps option, simply moving the mouse and scrolling a github issues page in firefox drops to below 14 fps.

Edit 2: Turning animations to “immediate” improves some but it still seems slower (not sure how to revert to test it)

Is there anything that may have caused this that I can check?

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2

Sounds like 494459 – kwin_wayland 6.2.0 Consumes All CPU Resources

Is your CPU usage really high? Are you running Neon in a VM?

3

Not in a vm but yes kwin_wayland is using 250-400% cpu. Just have with terminal with top open.

Thanks, will take a look at that issue.

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4

I also suffer from mouse and animations slowness in Plasma 6.2, but kwin_wayland doesn’t consume high CPU and there is enough RAM for it.

5

I right clicked on the blinking KDE nomodeset taskbar icon and “killed” it and now kwin_wayland is down to 15 to 30%. The icon was blinking much faster than i remembered.

Dragging resizing or dragging windows still makes it jump to 400% and all inputs seem to just be laggy…

6

I have same experience with Arch Linux and Plasma 6.1

7

I built kwin locally and ran perf as metioned in the bug above (bugzilla seems to be down). It looks like it has something to do with shading?

Screenshot_20241015_114259
Screenshot_20241015_1142591904×605 95.9 KB

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8

I tried adding KWIN_DRM_DISABLE_TRIPLE_BUFFERING=1 to /etc/environment and restarting but that also did not improve things (as mentioned in 488843 – Triple buffering causing stuttering)