https://bugs.kde.org/show_bug.cgi?id=528243
Bug ID: 528243
Summary: The compositor is slower than the previous version
like 100ms or so.
Classification: Plasma
Product: kwin
Version First 6.8.2
Reported In:
Platform: CachyOS
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: performance
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Title: Windowed-mode performance regression at 4K compared to 6.8.1 (fullscreen
unaffected)
DESCRIPTION
KWin is noticeably slower at 3840x2160 compared with the previous version
(6.8.1). I'm testing with a Rust application rendering through Vulkan. The
application runs fine in fullscreen, but in windowed mode the frame time is
about 100 ms higher in some cases on the affected version. Downgrading only the
kwin package
to 6.8.1 restores the previous performance.
The difference is not dramatic in absolute terms, but it is a significant
regression for a compositor, so it deserves a careful look. Fullscreen
being unaffected points at the composition path rather than the application.
TEST CONDITIONS
- Application: Rust + Vulkan, same build, window size and scene on both
versions
- CPU scheduler set to maximum performance, and process priority raised,
so scheduling is not the limiting factor
- Compared kwin 6.8.1 (good) against [affected version: 6.8.1-2.1 / 6.8.2]
- Logged out and back in after each kwin change
STEPS TO REPRODUCE
1. Run some Vulkan application windowed in version 6.8.1
2. Run the same application windowed in version 6.8.2
3. Compare the perfomance
OBSERVED RESULT
The application in version 6.8.2 is running slower.
EXPECTED RESULT
Windowed performance equal to 6.8.1
ACTUAL
Windowed performance is ~100 ms/frame slower at 4K on the affected version.
SOFTWARE/OS VERSIONS
CachyOs Linux updated 11/2/26
KDE Plasma Version: 6.8.2
KDE Frameworks Version: 6.31.0
Qt Version: 6.12.0
ADDITIONAL INFORMATION
I'm running the NVIDIA OPEN drivers in 4k (3840x2160) resolution with an rtx
4090
$> nvidia-smi --query-gpu=driver_version --format=csv,noheader
615.78.08
--
You are receiving this mail because:
You are watching all bug changes.
