Bug 494251

Summary:	Performance regression on ARM (Pinebook Pro)
Product:	[Plasma] kwin	Reporter:	Gurenko Alex <agurenko>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	grave	CC:	adamw, kde, nate, p3ybnyhv, xaver.hugl
Priority:	NOR	Keywords:	regression
Version First Reported In:	6.2.0
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Gurenko Alex 2024-10-07 16:54:55 UTC

SUMMARY

After upgrade from plasma 6.1.90 to 6.2.0 the performance is heavily regressed. The mouse stutters every second when moved over a window and very heavily stuttering when touching the task bar. Performance is fine when only showing desktop.

STEPS TO REPRODUCE
1. Open a terminal in a full screen
2. Move the mouse over the terminal and out to the taskbar area

OBSERVED RESULT

Heavy mouse and system stutter. CPU shows ~25% load for the app, plasmashell and kwin_wayland

EXPECTED RESULT

No stutter or increased CPU load is observed.

SOFTWARE/OS VERSIONS

Operating System: Fedora Linux 41
KDE Plasma Version: 6.2.0
KDE Frameworks Version: 6.7.0
Qt Version: 6.7.2
Kernel Version: 6.11.2-300.fc41.aarch64 (64-bit)
Graphics Platform: Wayland
Processors: 4 × ARM Cortex-A53, 2 × ARM Cortex-A72
Memory: 3.7 GiB of RAM
Graphics Processor: Mali-T860
Product Name: Pine64 Pinebook Pro

ADDITIONAL INFORMATION
Everything was working as expected on 6.1.90

Comment 1 Gurenko Alex 2024-10-07 16:56:13 UTC

Video showing the issue: https://drive.proton.me/urls/FED55JV09M#Bib65kbJxW7h

Comment 2 David Edmundson 2024-10-16 13:32:36 UTC

Can you confirm if performance is still the same after wiping .config/kwinrc

Comment 3 Gurenko Alex 2024-10-16 13:48:52 UTC

(In reply to David Edmundson from comment #2)
> Can you confirm if performance is still the same after wiping .config/kwinrc

I've removed said file, rebooted and the issue is still there. I also noticed that overview effect is now broken (shows black screen) and following appears in the logs:

Oct 16 15:44:57 kwin_wayland[1575]: kwin_scene_opengl: 0x4: GL_INVALID_OPERATION in glDrawElements
Oct 16 15:44:57 kwin_wayland[1575]: kwin_scene_opengl: 0x4: GL_INVALID_OPERATION in glVertexAttribPointer(no array object bound)
Oct 16 15:44:57 kwin_wayland[1575]: kwin_scene_opengl: 0x4: GL_INVALID_OPERATION in glVertexAttribPointer(no array object bound)
Oct 16 15:44:57 kwin_wayland[1575]: kwin_scene_opengl: 0x4: GL_INVALID_OPERATION in glVertexAttribPointer(no array object bound)
Oct 16 15:44:57 kwin_wayland[1575]: kwin_scene_opengl: 0x4: GL_INVALID_OPERATION in glDrawElements

I'm waiting for the 6.2.1 to be build for F41, maybe the recent fixes for https://bugs.kde.org/show_bug.cgi?id=492152 will help with this regression as well?

Comment 4 Gurenko Alex 2024-10-17 09:18:59 UTC

Okay, good news, 6.2.1 fixes the performance regression. The notes for Fedora update mentions this:

```
This update re-applies a patch to fix poor performance when 3D acceleration is not available. It was applied to 6.1.90, but lost in the 6.2.0 update.
```
Which maybe the culprit of the regression? I'm not sure which patch exactly is referenced, but here it is.

Comment 5 Adam Williamson 2024-10-17 16:10:45 UTC

For the record, that was tracked as https://bugs.kde.org/show_bug.cgi?id=493295 and fixed with https://invent.kde.org/plasma/kwin/-/commit/9370f7d19e4a047c72981d5b8f46a24eefd7cc83 .

Comment 6 Nate Graham 2024-10-17 16:12:04 UTC


*** This bug has been marked as a duplicate of bug 493295 ***