High CPU usage by kwin_wayland and plasmashell when idle

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1

Hi All,

On my desktop I notice that kwin_wayland and plasmashell have CPU usage of around 10% even when there is essentially nothing open / running. I don’t have any fancy desktop widgets either.

On my other systems the CPU usage is negligible when the system is idle.

Does anyone else have a similar problem, or know how I could go about fixing the issue. I’m using Plasma 6.3.4 on Arch

Thanks in advance

GI

1 Like
2

Update – System Settings → General Behavior → Animation Speed set to instant and the problem seems to have reduced. If I can confirm it completely went away, I’ll report back.

3

Both ?
That’s strange. The two processes are quite independent.
What settings do you use, like the theme?
Did you reboot since you last updated ?

You can report even now, this isn’t expected.
Your setup matter kinfo output is important.

Reporting it will help people facing the issue and prevent them to find or use a workaround, even you later. Up to you.

4

Yes, about 10% CPU usage of both kwin_wayland and plasmashell. I would often run

systemctl --user restart plasma-plasmashell.service

to restart plasmashell; but it would soon take up CPU. I’m using the default theme (Breeze or Breeze Dark), and my kinfo output is below:

Operating System: Arch Linux 
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.3
Kernel Version: 6.12.21-1-lts (64-bit)
Graphics Platform: Wayland
Processors: 16 × Intel® Core™ i9-9900 CPU @ 3.10GHz
Memory: 62.7 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 630

So far the problem hasn’t returned (with instant animations). If I can confirm it’s a bug and reliably reproduce it I’ll report it. But for now the problem seems to have gone away…

Any thoughts / suggestions are appreciated.

Thanks!

5

Did you reboot ?
After an important update, you need to reboot, or the binaries won’t be able to work properly.
plasma uses other important daemons, that need restarting like powerdevild, or kscreend for instance. If they don’t work correctly or are not what kwin or plasma expect a CPU usage is a possible outcome.

Reboot after plasma update.

Login-out can be not enough because some daemons and libraries are not part of plasma (udisks, nm…) and can cause similar issues.

6

Thanks; yes I did reboot, and it had no effect on the issue.

The animation speed instant seems to have done the trick though. Been a week and I don’t see the high CPU usage anymore!