Bug 501574

Summary:	Alt + Tab gets gradually slower over time
Product:	[Plasma] kwin	Reporter:	Alice <ali.alice3>
Component:	tabbox	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	nate
Priority:	NOR
Version First Reported In:	6.3.3
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	JournalCTL logs from KWIN GPU information System Information Plasmashell logs

Description Alice 2025-03-16 13:33:10 UTC

Created attachment 179451 [details]
JournalCTL logs from KWIN

SUMMARY
ALT + TAB becomes slower over time, taking longer and longer to display the next window when pressing the combination.

STEPS TO REPRODUCE
1. Use KDE Plasma as normal for a few hours, alt tab frequently, I used Audacity, and I closed it quite a lot while transferring sound files one at a time from my local storage to my media server using the split view.

OBSERVED RESULT
You'll see a delay of 1-2 seconds when switching tabs that won't go away no matter how many windows or processes you close. Everything else should perform as expected.

EXPECTED RESULT
Alt + Tab not slowing down at all after several hours.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 6.3.3
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.2

ADDITIONAL INFORMATION

Comment 1 Alice 2025-03-16 13:37:39 UTC

Forgot to add, I'm using the 6.13.6-zen1-1-zen kernel (64-bit).

Comment 2 Alice 2025-03-16 13:38:42 UTC

Created attachment 179453 [details]
GPU information

Comment 3 Alice 2025-03-16 13:39:00 UTC

Created attachment 179454 [details]
System Information

Comment 4 Alice 2025-03-16 13:39:57 UTC

Created attachment 179455 [details]
Plasmashell logs

Comment 5 Alice 2025-03-17 22:56:22 UTC

So I've done some using of my computer for a few hours, and it's definitely the combination of what I was doing with Audacity, Dolphin and transferring files. The alt tab is still fine even after sleep mode which was another theory of mine I had. Hopefully replicating it will show some possible results on your end?