Bug 485067 - [Nvidia][X11] High cpu usage of kscreenlocker_greet and plasmashell processes after switching users
Summary: [Nvidia][X11] High cpu usage of kscreenlocker_greet and plasmashell process...
Status: REPORTED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Screen locking (other bugs)
Version First Reported In: 6.2.4
Platform: openSUSE Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords: X11-only
: 486788 (view as bug list)
Depends on:
Blocks:
 
Reported: 2024-04-05 07:12 UTC by Vadym Krevs
Modified: 2026-04-08 13:11 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
qdbus-qt5 org.kde.KWin /KWin supportInformation (6.76 KB, text/plain)
2024-04-05 07:12 UTC, Vadym Krevs
Details
perf report for the plasmashell process with high CPU usage (1.77 MB, text/plain)
2024-04-05 07:13 UTC, Vadym Krevs
Details
qdbus-qt5 org.kde.KWin /KWin supportInformation (6.46 KB, text/plain)
2025-05-10 10:56 UTC, Vadym Krevs
Details
qdbus6 org.kde.KWin /KWin supportInformation (6.46 KB, text/plain)
2025-05-10 10:57 UTC, Vadym Krevs
Details
qdbus6 org.kde.KWin /KWin supportInformation from my current Leap 16.0 system (6.66 KB, text/plain)
2026-04-06 18:24 UTC, Vadym Krevs
Details

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Description Vadym Krevs 2024-04-05 07:12:20 UTC
Created attachment 168172 [details]
qdbus-qt5 org.kde.KWin /KWin supportInformation

SUMMARY
High cpu usage of  kscreenlocker_greet and plasmashell  processes after switching users.

Originally reported via https://bugs.kde.org/show_bug.cgi?id=347772#c75, created a new issue as requested by Nate in https://bugs.kde.org/show_bug.cgi?id=347772#c77.

Reproducible: Always. 
Started to happen after replacing the old AMD video card with the NVIDIA video card.

Steps to reproduce:
1. Login as user1
2.  Switch user to user2
3. Observe kscreenlocker_greet and plasmashell processes running as user1 begin to consume 100% CPU.
4. Log off user2 and log back in as user1.
5. High CPU usage disappears.

The workaround from https://bugs.kde.org/show_bug.cgi?id=347772#c22 does not help.
Output of "qdbus-qt5 org.kde.KWin /KWin supportInformation" is attached.


SOFTWARE/OS VERSIONS
Operating System: openSUSE Leap 15.5
KDE Plasma Version: 5.27.11
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.12
Kernel Version: 5.14.21-150500.55.52-default (64-bit)
Graphics Platform: X11
Graphics Processor: NVIDIA GeForce RTX 4060 Ti/PCIe/SSE2
Nvidia drivers: nvidia-video-G06-550.67-lp155.20.1.x86_64)
Comment 1 Vadym Krevs 2024-04-05 07:13:01 UTC
Output of the following is attached.
perf record -p $(pidof plasmashell) -e cpu-cycles --call-graph fp
perf report > perf.report
Comment 2 Vadym Krevs 2024-04-05 07:13:33 UTC
Created attachment 168173 [details]
perf report for the plasmashell process with high CPU usage
Comment 3 TraceyC 2025-01-14 01:22:00 UTC
*** Bug 486788 has been marked as a duplicate of this bug. ***
Comment 4 Nate Graham 2025-05-09 17:33:55 UTC
Thank you for the bug report! I'm so sorry we weren't able to get to it yet, especially given the debugging you've already done.

However I can't reproduce this on my system running git master. Can you check and see if it's still an issue in Plasma 6.3.5 or later? Thanks a lot!
Comment 5 Vadym Krevs 2025-05-10 10:56:13 UTC
Still an issue on:
Operating System: openSUSE Leap 15.6
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.14.0
Qt Version: 6.9.0
Kernel Version: 6.4.0-150600.23.47-default (64-bit)
Graphics Platform: X11
Processors: 32 × AMD Ryzen 9 5950X 16-Core Processor
Memory: 125.7 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 4060 Ti
Manufacturer: ASUS

Outputs of  "qdbus-qt5 org.kde.KWin /KWin supportInformation" and "qdbus6 org.kde.KWin /KWin supportInformation"  are attached.
Comment 6 Vadym Krevs 2025-05-10 10:56:47 UTC
Created attachment 181131 [details]
qdbus-qt5 org.kde.KWin /KWin supportInformation
Comment 7 Vadym Krevs 2025-05-10 10:57:11 UTC
Created attachment 181132 [details]
qdbus6 org.kde.KWin /KWin supportInformation
Comment 8 Robin Laing 2025-12-12 07:43:41 UTC
Had similar issues.  Changed from sddm to gdm and problem lessened.  Changed video card with more vram have not had an issue since.  I did read an article about sddm not working well with Wayland and I had used gdm before.  

Can now have at least three sessions running with no issues.  

Check amount of vram that is being used.  I am finding that over 1Gig of Vram is required for each session.  Looking at a remote machine that is in power saving mode, vram is about 1.6Gig for a single session.  Kscreenlocker is using 286MiB of that session.
Comment 9 Vadym Krevs 2025-12-12 08:56:08 UTC Comment hidden (spam)
Comment 10 Marcelo Lacerda 2026-03-12 00:15:34 UTC
I can't reproduce it either. I'm using sddm with wayland as well.

Operating System: Arch Linux 
KDE Plasma Version: 6.6.2
KDE Frameworks Version: 6.23.0
Qt Version: 6.10.2
Kernel Version: 6.19.6-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 5600G with Radeon Graphics
Memory: 32 GiB of RAM (31.1 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 4060
Manufacturer: ASUS
Comment 11 Nate Graham 2026-03-17 13:59:34 UTC
Vadym, are you able to reproduce this issue on Wayland too? Or only on X11?
Comment 12 Vadym Krevs 2026-03-19 08:28:42 UTC Comment hidden (spam)
Comment 13 Bug Janitor Service 2026-04-03 03:47:22 UTC Comment hidden (spam)
Comment 14 Vadym Krevs 2026-04-06 18:20:36 UTC
(In reply to Vadym Krevs from comment #12)
> (In reply to Nate Graham from comment #11)
> > Vadym, are you able to reproduce this issue on Wayland too? Or only on X11?
> 
> To be honest, the lack of progress on this issue (since comment 7) forced me
> to switch my workflow and stop using this feature. I will soon be upgrading
> to openSUSE 16.0, will test after upgrade.

https://bugs.kde.org/show_bug.cgi?id=485067

(In reply to Vadym Krevs from comment #12)
> (In reply to Nate Graham from comment #11)
> > Vadym, are you able to reproduce this issue on Wayland too? Or only on X11?
>
> To be honest, the lack of progress on this issue (since comment 7) forced me
> to switch my workflow and stop using this feature. I will soon be upgrading
> to openSUSE 16.0, will test after upgrade.

Well, I've tried.

I've updated my openSUSE Leap 15.6 system to Leap 16.0 on Sunday and everything is working using X11.

Today I've attempted to login using Plasma/Wayland session from SDDM in order to reproduce this defect.

Sadly, the screen goes black and that's it. I ssh'd into the desktop from another laptop before attempting this and ran top and observed kwin_wayland process initially spiking up to consume ~2000% CPU (my desktop has a 16 core/32-thread processor hence the percentages) and then settle on constant 30-40% CPU usage.  It seems that there was an attempt to restore the Plasma session - System Monitor was also running and constantly consuming 30-40% CPU. I waited for a couple of minutes - thinking maybe some Mesa caches need regenerating, etc - but nothing changed, the screen stayed black and these two processes (as well as some others) were constantly spinning at 30-40% CPU. I guess I have some "fun" to look forward to when Plasma drops support for X11 ...

Rebooted and tried again - same results. Switched to runlevel 3 and then back to 5 and attempted to login into Plasma/X11 session from SDDM and attempted to reproduce the issue as described in comment #1. Sadly, the issue still happens exactly as described there.


This is my current hardware/software setup:

Operating System: openSUSE Leap 16.0
KDE Plasma Version: 6.6.3
KDE Frameworks Version: 6.24.0
Qt Version: 6.11.0
Kernel Version: 6.12.0-160000.27-default (64-bit)
Graphics Platform: X11
Processors: 32 × AMD Ryzen 9 5950X 16-Core Processor
Memory: 128 GiB of RAM (125.7 GiB usable)
Graphics Processor 1: NVIDIA GeForce RTX 4060 Ti/PCIe/SSE2
Manufacturer: ASUS
Nvidia drivers: nvidia-driver-G06-kmp-default-580.142_k6.12.0_160000.27-lp160.46.3.x86_64

$ inxi -aG
Graphics:
  Device-1: NVIDIA AD106 [GeForce RTX 4060 Ti 16GB] vendor: Micro-Star MSI
    driver: nvidia v: 580.142 alternate: nouveau,nvidia_drm non-free: 550.xx+
    status: current (as of 2024-09) arch: Lovelace code: AD1xx
    process: TSMC n4 (5nm) built: 2022+ pcie: gen: 2 speed: 5 GT/s lanes: 8
    link-max: gen: 4 speed: 16 GT/s ports: active: none off: DP-1
    empty: DP-2,DP-3,HDMI-A-1 bus-ID: 08:00.0 chip-ID: 10de:2805
    class-ID: 0300
  Device-2: Logitech Logitech Webcam C925e driver: snd-usb-audio,uvcvideo
    type: USB rev: 2.0 speed: 480 Mb/s lanes: 1 mode: 2.0 bus-ID: 3-2:3
    chip-ID: 046d:085b class-ID: 0102 serial: 9F4B7C5F
  Display: x11 server: X.Org v: 21.1.15 with: Xwayland v: 24.1.6
    compositor: kwin_x11 driver: X: loaded: nvidia unloaded: modesetting,vesa
    alternate: fbdev,nouveau,nv gpu: nvidia,nvidia-nvswitch display-ID: :0
    screens: 1
  Screen-1: 0 s-res: 3840x2160 s-dpi: 120 s-size: 813x457mm (32.01x17.99")
    s-diag: 933mm (36.72")
  Monitor-1: DP-0 res: 3840x2160 hz: 60 dpi: 140
    size: 698x393mm (27.48x15.47") diag: 801mm (31.54") modes: N/A
  API: OpenGL v: 4.6.0 vendor: nvidia v: 580.142 glx-v: 1.4
    direct-render: yes renderer: NVIDIA GeForce RTX 4060 Ti/PCIe/SSE2
    memory: 15.62 GiB
  API: Vulkan v: 1.4.309 layers: 3 device: 0 type: discrete-gpu name: NVIDIA
    GeForce RTX 4060 Ti driver: N/A device-ID: 10de:2805 surfaces: xcb,xlib
  API: EGL Message: EGL data requires eglinfo. Check --recommends.
Comment 15 Vadym Krevs 2026-04-06 18:24:02 UTC
Created attachment 191332 [details]
qdbus6 org.kde.KWin /KWin supportInformation from my current Leap 16.0 system
Comment 16 Vadym Krevs 2026-04-06 18:25:03 UTC
Attached output of "qdbus6 org.kde.KWin /KWin supportInformation" from my current Leap 16.0 system.
Comment 17 Vadym Krevs 2026-04-07 18:12:09 UTC Comment hidden (spam)
Comment 18 Marcelo Lacerda 2026-04-07 22:09:03 UTC Comment hidden (spam)
Comment 19 Vadym Krevs 2026-04-08 07:03:15 UTC
(In reply to Marcelo Lacerda from comment #18)
> So, wouldn't it be better for you to close this issue and reopen the other
> ones?

My issue is on x11 and still not fixed. And I have no time to troubleshoot new issues arising from the switch to wayland.
Comment 20 TraceyC 2026-04-08 13:11:52 UTC
(In reply to Vadym Krevs from comment #19)
> My issue is on x11 and still not fixed. And I have no time to troubleshoot
> new issues arising from the switch to wayland.

Fair enough. I understand you're still seeing kscreenlocker_greet and plasmashell  processes use a lot of CPU after switching users. This report is only for that issue, let's keep the conversation focused on that. The more focused the conversation, the easier it is for the developers to understand the report and fix the bug.