High CPU usage during screen lock

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1

Howdy! I’m currently using Plasma 6.2 via Neon. I recently discovered some really high CPU usage after I lock the screen. I’ll lock the screen, then see this via top if I ssh in via another machine:

   2238 root      20   0 1410792 482684 117460 S  57.8   0.7  57:07.70 /usr/lib/xorg/Xorg -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_QwTqAk -noreset -displayfd 16
   2598 jkugler   20   0 2549748 259840 164884 R  53.5   0.4  55:34.55 /usr/bin/kwin_x11 --replace
   2595 jkugler   20   0  811788 135820 122736 S  12.0   0.2  11:01.71 /usr/bin/ksmserver
  52344 jkugler   20   0 2539656 252772 155856 S   6.6   0.4   0:08.43 /lib/x86_64-linux-gnu/libexec/kscreenlocker_greet --immediateLock --graceTime 5000 --ksldfd 39

Xorg is using nearly 60% CPU, and kwin_x11 is using over 50% CPU. ksm_server and kscreenlock_greet aren’t exactly idle either.

This continues even after the screen goes blank (black). FYI, this is a 4K external monitor.

I would expect the CPU usage to go to near zero since the machine is idle. What are the best areas in which to start troubleshooting this?

Thanks!

Update: watching the CPU usage after lock, there are a LOT of KDE processes using anywhere from 2%CPU to 4.5% CPU (or more) after I lock the screen: things like all the Akonadi processes, kded6, Kmail, Konversation, as well as other processes that sit at 0% CPU when the screen isn’t locked. It’s very strange.

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Hi - it looks like you’re experiencing 484323 – High CPU load of kwin_x11 when locking or turning off the screen - if there are any observations you’ve made on your system that might contribute to the investigation of that bug, adding them as comments there would be much appreciated!

If there’s nothing specific that needs added, then that bug report can be the spot to follow progress toward resolution by adding yourself to the CC list up in the top section of the page.

Hope that helps,

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Thanks, I appreciate it. What’s odd is that it only recently seemed to manifest, and I’ve been running Neon for a few years now. Odd that I haven’t seen it before.