Bug 475872

Summary:	With an NVIDIA GPU on X11, resizing windows choppy when Pager widget is enabled
Product:	[Plasma] kwin	Reporter:	Klaus Zipfel <klaus>
Component:	performance	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	CONFIRMED ---
Severity:	normal	CC:	ditto.ditto, hein, kde, nate, postix, xalt7x.service
Priority:	NOR	Keywords:	X11-only
Version:	5.27.8
Target Milestone:	---
Platform:	Manjaro
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=475468
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Klaus Zipfel 2023-10-20 11:01:45 UTC

Resizing a window becomes extremely choppy when the pager is added to the taskbar on systems using an nVidia GPU.

Only tested on X11 with proprietary nVidia driver (Version 535.113.01).


STEPS TO REPRODUCE
1. Have a dedicated nVidia GPU as primary GPU + proprietary nVidia driver
2. Add the pager to your taskbar
3. Open e.g. Dolphin and resize it. It feels choppy and delayed
4. Remove all pagers from the taskbar
5. Resizing e.g. Dolphin now is fluent.

OBSERVED RESULT
Choppy resizing

EXPECTED RESULT
Fluent resizing

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:  Manjaro Linux (latest)
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.11

ADDITIONAL INFORMATION
[1] Link to reddit discussion: https://www.reddit.com/r/kde/comments/yogjmu/extreme_lag_on_window_redrawresize

Comment 1 Nate Graham 2023-10-20 16:46:25 UTC

Does it happen on Wayland as well?

Comment 2 Klaus Zipfel 2023-10-24 08:41:46 UTC

I just tested it on Wayland, which seems to be unaffected by this bug.

Comment 3 ratijas 2024-05-03 14:40:17 UTC

Quite interesting. I can confirm on X11 with proprietary NVIDIA driver on Arch.

Without the Pager, QtWidgets apps resizing is butter-smooth, and QtQuick ones still stagger but less. Panel floating/defloating animation is also affected: in a presence of a Pager the transition is like just first 1-2 frames and then half a second later suddenly just to the last frames; but without a Pager it is still somewhat of a slideshow but not *that* bad.

Comment 4 Yevhen Popok 2024-08-11 16:02:02 UTC

I wonder if the option to disable window preview/outline (scheduled for Plasma 6.2) helps with this.
https://bugs.kde.org/show_bug.cgi?id=392484

Comment 5 ditto.ditto 2024-09-03 09:01:02 UTC

I can confirm this bug  exits on X11 with nvidia open driver on openSUSE as well

Comment 6 TraceyC 2025-02-24 17:58:33 UTC

Adding the x11-only keyword