Bug 512796

Summary: Overview lags when opening while system is under massive load
Product: [Plasma] kwin Reporter: LucasGGamerM <LucasGGamerM>
Component: effects-overviewAssignee: KWin default assignee <kwin-bugs-null>
Status: REPORTED ---    
Severity: normal CC: nate
Priority: NOR Keywords: efficiency-and-performance
Version First Reported In: 6.5.2   
Target Milestone: ---   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description LucasGGamerM 2025-11-30 14:30:13 UTC 
SUMMARY
The overview causes unnecessary disk access, making it slow the first time opening, and potentially causing the whole compositor to hang when there is IO heavy operations running. 

STEPS TO REPRODUCE
1. Have two monitors
2. Run a game in the primary monitor
3. Compress a huge directory into a tar.gz archive
4. Open the overview

OBSERVED RESULT
The whole compositor hangs for a long time (I waited around 3 minutes until a new frame was rendered by the compositor, and had to force shutdown my machine)

EXPECTED RESULT
Have the effect run without causing the system to hang

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Operating System: Fedora Linux 43
KDE Plasma Version: 6.5.2
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.0
Kernel Version: 6.17.7-300.fc43.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800H with Radeon Graphics
Memory: 32 GiB of RAM (29.2 GiB usable)
Graphics Processor 1: AMD Radeon Graphics
Graphics Processor 2: NVIDIA GeForce RTX 3050 Laptop GPU

ADDITIONAL INFORMATION
The effect shouldn't cause disk read operations, specially rendering blocking ones
Comment 1 Nate Graham 2025-12-11 17:34:16 UTC 
It sounds like you're intentionally putting your system under massive load and expecting perfect performance? 3 minutes is definitely too long, but you'll probably need to temper your expectations. For example, it's not reasonable to expect that opening the effect causes no disk reads. Because the effect has configuration options, it needs to read the configuration data to get the current status, and that data lives on disk, in files.
Comment 2 LucasGGamerM 2025-12-11 17:46:56 UTC 
I know it may take a while to open when system load is at it's peak, but the main problem here is that the loading of the effect is a render blocker, even when there is no load on the system.

I just found it frustrating that a single missed mouse flick during heavy system load is enough to make kwin give up drawing things on the screen. The same thing does not happen on other plasma components, such as the wifi applet, as even if it becomes slow to open during high system load, it won't stop kde from becoming completely unresponsive (the problem with the overview is that it makes even the mouse cursor stpp responding).

I don't wish for perfect performance, I just want the effect not to block the main compositor render loop.