Bug 489068

Summary:	High CPU usage with Twitch chat and heavy lag
Product:	[Plasma] kwin	Reporter:	salvatore.cresce
Component:	performance	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	xaver.hugl
Priority:	NOR
Version First Reported In:	6.0.5
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description salvatore.cresce 2024-06-23 20:43:46 UTC

SUMMARY: kwin_wayland uses a lot of CPU when the chat on Twitch is full of messages or emotes. Also, the webpage lags a lot until the chat is disabled. 


STEPS TO REPRODUCE
1. Open a Twitch channel that is full of users using the chat. This happens with Chromium-based browsers and with Firefox.
2. kwin_wayland uses a lot of CPU and the web page lags
3. the chat can be closed, performance restored a bit (doesn't lag anymore, still a lot of CPU usage)

opensuse Slowroll, updated. Nvidia drivers 550, external monitor (USB C to DisplayPort), Wayland session.

Comment 1 Zamundaaa 2025-10-17 12:07:49 UTC

> Nvidia drivers 550, external monitor
Multi GPU copies are known to be very slow and inefficient on NVidia.
On the latest KWin + NVidia drivers, there should at least not be a lot of CPU usage though; do you still see that in Plasma 6.4?

Comment 2 salvatore.cresce 2025-10-17 12:12:19 UTC

(In reply to Zamundaaa from comment #1)
> > Nvidia drivers 550, external monitor
> Multi GPU copies are known to be very slow and inefficient on NVidia.
> On the latest KWin + NVidia drivers, there should at least not be a lot of
> CPU usage though; do you still see that in Plasma 6.4?

It's going better on updated Aurora OS (Plasma 6.4.x) with latest stable Nvidia drivers.

Comment 3 Zamundaaa 2025-10-17 13:46:24 UTC

Cool