Bug 477357

Summary:	Choppy scrolling in Plasma Search KCM
Product:	[Applications] systemsettings	Reporter:	Patrick Silva <bugseforuns>
Component:	kcm_plasmasearch	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	CONFIRMED ---
Severity:	minor	CC:	agurenko, alexander.lohnau, bharadwaj.raju777, nate, nicolas.fella, qydwhotmail
Priority:	NOR	Keywords:	efficiency-and-performance, qt6
Version:	5.27.80
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Profile

Description Patrick Silva 2023-11-22 10:09:46 UTC

STEPS TO REPRODUCE
1. open Plasma Search KCM
2. scroll though the plugins list - I use a touchpad
3. 

OBSERVED RESULT
choppy scrolling

EXPECTED RESULT
smooth scrolling

SOFTWARE/OS VERSIONS
Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.81.80
KDE Frameworks Version: 5.245.0
Qt Version: 6.6.0
Graphics Platform: Wayland

Comment 1 Bharadwaj Raju 2023-11-22 12:35:25 UTC

`reuseItems: true` greatly improves the performance after the first scroll.

But I want to profile it and find out why it's taking so long in the first place.

Comment 2 Nicolas Fella 2023-11-22 19:00:29 UTC

Created attachment 163372 [details]
Profile

Profiling suggests there's unusually much time spent in PlasmaDesktopTheme::syncColors() (qqc2-desktop-style)

Interestingly e.g. the kded KCM doesn't seem to be affected

Comment 3 Nate Graham 2023-11-27 02:12:48 UTC

Can also reproduce. +1 for setting reuseItems here, in addition to anything else we do to lighten up these delegates or make deeper fixes.

Comment 4 Nicolas Fella 2024-01-08 23:48:03 UTC

The difference to other KCMs seems to be that PluginDelegate uses Kirigami.ActionToolBar