Bug 483698 - choppy framerate in X11 after upgrade to Plasma 6
Summary: choppy framerate in X11 after upgrade to Plasma 6
Alias: None
Product: kwin
Classification: Plasma
Component: performance (show other bugs)
Version: 6.0.2
Platform: Neon Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
Keywords: qt6, regression
Depends on:
Reported: 2024-03-15 17:36 UTC by S. Christian Collins
Modified: 2024-06-26 23:32 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In: 6.1.1
Sentry Crash Report:

additional information from Info Center (22.60 KB, application/gzip)
2024-03-15 17:36 UTC, S. Christian Collins

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Description S. Christian Collins 2024-03-15 17:36:47 UTC
Created attachment 167280 [details]
additional information from Info Center

Since upgrading my laptop to Plasma 6, the compositor performance in X11 has become very choppy. I previously had smooth 60 fps for desktop effects, but now I get around 32-35 fps when moving a window around and 45-50 fps when doing nothing. Switching to Wayland, everything stays at a smooth 60 fps.

Here is a video comparing X11 vs. Wayland performance on my laptop: https://youtu.be/O5LSSBpYJW0

Linux: KDE neon 6.0 User Edition
KDE Plasma Version: 6.0.2
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2

PC: HP Pavilion m6-1035dx
CPU/GPU: AMD A10-4600M 2.3 GHz quad-core APU with Trinity [Radeon HD 7660G] Graphics (using radeon driver)
RAM: 8GB DDR3 (2x 4GB PC3-12800 1600 MHz), 7.2GB usable

I have attached additional system information from Info Center. I also use the following X11 settings for my GPU, though deleting this file appears to make no difference to performance:
Section "Device"
    Identifier "Card0"
    Driver "radeon"
    Option "AccelMethod" "glamor"
    Option "TearFree" "off"
    Option "DRI3" "1"
Comment 1 S. Christian Collins 2024-03-15 18:31:27 UTC
Testing with the KWIN_X11_NO_SYNC_TO_VBLANK=1 environment variable set, I am now getting well over 60 FPS constantly, so my issue would seem to be possibly vsync related.
Comment 2 S. Christian Collins 2024-03-15 18:46:09 UTC
I also tested the following environment variables found in other framerate-related bug reports, but neither of them had any affect in my case:
Comment 3 Zamundaaa 2024-06-09 16:50:59 UTC
Please attach the output of
> glxinfo | grep timer_query
Comment 4 S. Christian Collins 2024-06-10 19:23:06 UTC
(In reply to Zamundaaa from comment #3)
> Please attach the output of
> > glxinfo | grep timer_query

    GL_ARB_texture_view, GL_ARB_timer_query, GL_ARB_transform_feedback2, 
    GL_EXT_texture_swizzle, GL_EXT_timer_query, GL_EXT_transform_feedback, 
    GL_ARB_texture_swizzle, GL_ARB_texture_view, GL_ARB_timer_query, 
    GL_EXT_texture_snorm, GL_EXT_texture_swizzle, GL_EXT_timer_query, 
    GL_EXT_discard_framebuffer, GL_EXT_disjoint_timer_query,
Comment 5 Bug Janitor Service 2024-06-25 03:47:30 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:

If you have already provided the requested information, please
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Comment 6 Zamundaaa 2024-06-25 12:07:14 UTC
Okay, so the OpenGL extensions KWin uses for render time tracking are supported... 6.1.1 will contain some code that helps debug this sort of thing.
Could you check if the problem is still there with 6.1, and if it is, run 6.1.1 with the KWIN_LOG_PERFORMANCE_DATA=1 environment variable set, and upload the performance logs KWin saves in your home folder?
Comment 7 S. Christian Collins 2024-06-26 14:13:27 UTC
This issue is now resolved in Plasma 6.1.1. I am now getting smooth desktop response in Plasma again. Thank you!