Bug 511265 - Plasmashell consumes 10% of CPU processes when Slideshow is active in System Settings
Summary: Plasmashell consumes 10% of CPU processes when Slideshow is active in System ...
Status: VERIFIED FIXED
Alias: None
Product: plasmashell
Classification: Plasma
Component: Image & Slideshow wallpaper plugins (other bugs)
Version First Reported In: 6.5.0
Platform: Arch Linux Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords: efficiency-and-performance
Depends on:
Blocks:
 
Reported: 2025-10-28 12:19 UTC by Luis
Modified: 2025-11-23 13:54 UTC (History)
8 users (show)

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


Attachments
Normal operation, with "Picture of the Day" selected. (1.10 KB, application/gzip)
2025-11-22 15:07 UTC, Sam Birch
Details
High CPU usage, with "Slideshow" selected (980 bytes, application/gzip)
2025-11-22 15:08 UTC, Sam Birch
Details

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Description Luis 2025-10-28 12:19:49 UTC
***
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***

SUMMARY
Plasmashell consumes 10% of CPU processes when Slideshow is active in System Settings

STEPS TO REPRODUCE
1. Select Slideshow in System Settings - Wallpapers
2. In HTOP process: /usr/bin/plasmashell --no-respawn jumps to almost 10% and multiple copies appear
3. Change from Slideshow to any other Wallpaper and plasmashell process returns to normal

OBSERVED RESULT


EXPECTED RESULT


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 6.5.0
KDE Plasma Version: 6.5.0
KDE Frameworks Version: 6.19.0
Qt Version: 6.10.0

ADDITIONAL INFORMATION
Kernel: 6.12.53-1-lts
Graphics: Wayland
Comment 1 TraceyC 2025-10-28 21:37:08 UTC
I'm not able to reproduce this with Plasma built from git-master on a system with an AMD GPU
System load avg .45 (8 core AMD CPU)

I *am* able to reproduce it with git-master on laptop with  an NVIDIA GPU
Note: there were multiple plasmashell processes before I changed the wallpaper of one monitor to slideshow, all showing 0% CPU
After switching the wallpaper to slideshow, they will briefly go up to 2.1, then back down briefly to 0, then back up 
System load avg 2.35 (16 core Intel CPU)
Comment 2 Nate Graham 2025-10-29 19:57:11 UTC
Can't reproduce on an AMD GPU either. I see no difference in plasmashell's CPU usage no matter what wallpaper plugin is shown on the page.

Luis, do you have an NVIDIA GPU as well?
Comment 3 Andrés 2025-10-30 23:24:53 UTC
I can reproduce this bug on my fully updated EndeavourOS machine.
As soon as I select the "Slideshow" option on System Settings -> Wallpaper, the processes "plasmashell" and "systemsettings" jump to about 300% CPU load each according to top. After waiting for a couple of minutes to see if the system is just loading the images, closing the System Settings window leaves only the "plasmashell" process displaying 300% CPU load.
Other options: Positioning: scaled and cropped; Switch dynamic wallpapers: based on whether...; Order: A to Z; Group by folders: yes; Change every: 1 hour
My wallpaper folder has 211 files with a combined size of 115.3 MiB.
I have no plasmoids or extensions installed. I'm using the default Breeze Dark theme.
Choosing the "Plain Color" option brings CPU usage back to normal.
I'd be happy to provide any other details.
Thanks to the KDE developers for their work.

My system (from Info Center):
Operating System: EndeavourOS 
KDE Plasma Version: 6.5.1
KDE Frameworks Version: 6.19.0
Qt Version: 6.10.0
Kernel Version: 6.17.5-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i3-N300
Memory: 16 GiB of RAM (15.3 GiB usable)
Graphics Processor: Intel® Graphics
Manufacturer: Acer
Product Name: Aspire AL14-31P
System Version: V1.11
Comment 4 Sdar 2025-11-01 16:26:52 UTC
Same as Andrés, htop showing a bit above 300% of cpu as soon as I select slideshow (no need to hit apply).

This is the `` journalctl -f `` output:

```
nov 01 16:46:40 xxxxxx-kde plasmashell[246153]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/SlideshowComponent.qml: No such file or directory
nov 01 16:46:40 xxxxxx-kde plasmashell[246153]: file:///usr/share/plasma/wallpapers/org.kde.slideshow/contents/ui/SlideshowComponent.qml:175:5: QML RowLayout: Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
nov 01 16:46:40 xxxxxx-kde plasmashell[246153]: file:///usr/share/plasma/wallpapers/org.kde.slideshow/contents/ui/SlideshowComponent.qml:175:5: QML RowLayout: Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
nov 01 16:46:40 xxxxxx-kde plasmashell[246153]: file:///usr/share/plasma/wallpapers/org.kde.slideshow/contents/ui/SlideshowComponent.qml:175:5: QML RowLayout: Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
nov 01 16:46:40 xxxxxx-kde plasmashell[246153]: file:///usr/share/plasma/wallpapers/org.kde.slideshow/contents/ui/SlideshowComponent.qml:175:5: QML RowLayout: Qt Quick Layouts: Detected recursive rearrange. Aborting after two iterations.
```

And I checked the file in this path does, indeed, not exists: /usr/share/plasma/wallpapers/org.kde.image/contents/ui/SlideshowComponent.qml

The issue started on 6.5.0 and still happens on 6.5.1, so far is the only major issue I've found, but till I found the culprit it made everything run so slow I ended loading a previous snapshot till I had some time to search for the problem.

In my case I'm using the X session (I just gave up trying to get the global or window menus work on mumble without having "unforeseen consequences") on an intel with uhd 630 graphics.
Comment 5 Bug Janitor Service 2025-11-06 09:14:47 UTC
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/5970
Comment 6 Vlad Zahorodnii 2025-11-06 17:06:56 UTC
Git commit 073925b67253d6432c799f4475faa5d073a29347 by Vlad Zahorodnii.
Committed on 06/11/2025 at 17:04.
Pushed by vladz into branch 'master'.

wallpapers/image: Fix high cpu usage when wallpaper dialog is open

The title and the author records are cached. But cache is not the right
abstraction for storing such information because more than 10 wallpapers
can be shown at the same time, which can trigger a feedback loop:
query metadata for an image => evacuate some metadata from a cache to
make space for the just loaded metadata => query metadata for an image
whose metadata has been just released (for example if the view side
wants it again) and so on.

This change makes the wallpaper model store background metadata in hash
tables in order to address high CPU usage.

M  +15   -24   wallpapers/image/plugin/model/abstractimagelistmodel.cpp
M  +2    -8    wallpapers/image/plugin/model/abstractimagelistmodel.h
M  +7    -9    wallpapers/image/plugin/model/imagelistmodel.cpp
M  +0    -1    wallpapers/image/plugin/model/packagelistmodel.cpp

https://invent.kde.org/plasma/plasma-workspace/-/commit/073925b67253d6432c799f4475faa5d073a29347
Comment 7 Bug Janitor Service 2025-11-06 17:07:38 UTC
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/5974
Comment 8 Vlad Zahorodnii 2025-11-06 17:30:05 UTC
Git commit 2b6d935cb0b8de46a619253f0392ac3484d2629e by Vlad Zahorodnii.
Committed on 06/11/2025 at 17:07.
Pushed by vladz into branch 'Plasma/6.5'.

wallpapers/image: Fix high cpu usage when wallpaper dialog is open

The title and the author records are cached. But cache is not the right
abstraction for storing such information because more than 10 wallpapers
can be shown at the same time, which can trigger a feedback loop:
query metadata for an image => evacuate some metadata from a cache to
make space for the just loaded metadata => query metadata for an image
whose metadata has been just released (for example if the view side
wants it again) and so on.

This change makes the wallpaper model store background metadata in hash
tables in order to address high CPU usage.


(cherry picked from commit 073925b67253d6432c799f4475faa5d073a29347)

Co-authored-by: Vlad Zahorodnii <vlad.zahorodnii@kde.org>

M  +15   -24   wallpapers/image/plugin/model/abstractimagelistmodel.cpp
M  +2    -8    wallpapers/image/plugin/model/abstractimagelistmodel.h
M  +7    -9    wallpapers/image/plugin/model/imagelistmodel.cpp
M  +0    -1    wallpapers/image/plugin/model/packagelistmodel.cpp

https://invent.kde.org/plasma/plasma-workspace/-/commit/2b6d935cb0b8de46a619253f0392ac3484d2629e
Comment 9 Nate Graham 2025-11-07 23:07:33 UTC
Please let us know if it's still an issue in Plasma 6.5.3 or later. Thanks!
Comment 10 Andrés 2025-11-18 16:03:27 UTC
I've just updated to Plasma 6.5.3-1 and I'm happy to report that the issue has been solved. Thanks!
I'm using EndeavourOS with KDE Plasma 6.5.3, KDE Frameworks 6.20.0, Qt 6.10.0, Kernel 6.17.8-arch1-1, and Wayland.
Comment 11 TraceyC 2025-11-18 18:40:35 UTC
That's great news, thanks for letting us know. I'm closing this report out for now. If the bug recurs, feel free to set this to REOPENED.
Comment 12 Sam Birch 2025-11-22 15:06:58 UTC
This is still happening for me in Plasma 6.5.2. In fact, I can trigger it just by opening Desktop Folder Settings > Wallpaper, and setting Wallpaper type to Slideshow. (I don't even have to click Apply.)

Operating System: Fedora Linux 42
KDE Plasma Version: 6.5.2
KDE Frameworks Version: 6.20.0
Qt Version: 6.9.3
Kernel Version: 6.17.8-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 7840HS w/ Radeon 780M Graphics
Memory: 32 GiB of RAM (30.6 GiB usable)
Graphics Processor: AMD Radeon 780M Graphics
Manufacturer: Framework
Product Name: Laptop 16 (AMD Ryzen 7040 Series)
System Version: A7
Comment 13 Sam Birch 2025-11-22 15:07:33 UTC
Created attachment 187063 [details]
Normal operation, with "Picture of the Day" selected.
Comment 14 Sam Birch 2025-11-22 15:08:41 UTC
Created attachment 187064 [details]
High CPU usage, with "Slideshow" selected

No idea of these traces will be helpful. Let me know if I can gather more data.
Comment 15 Sam Birch 2025-11-22 15:10:29 UTC
Oh, y'all said 6.5.3 or later. I'm so embarrassed. Please disregard.
Comment 16 Luis 2025-11-23 13:54:18 UTC
As the original reporter of the bug, I can confirm it is fixed in 6.5.3