Bug 271792

Summary:	kwin slow scrolling with compositing enabled
Product:	[Plasma] kwin	Reporter:	Roman K. <roman.karlstetter>
Component:	compositing	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	normal
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Roman K. 2011-04-26 18:44:30 UTC

Version:           unspecified (using KDE 4.6.2) 
OS:                Linux

Hi,
I just noticed today (after I accidentally disabled compositing) that scrolling in general, which means scrolling websites (firefox), source code (qt-creator), email-lists(kmail), terminals (konsole) but also an application I develop for a project at university (which implements zooming of a plotcurve but scrolling with the mouse wheel) are noticeable slower when compositing is enabled compared to when it is disabled.
I mean, all the thing work reasonable well also when compositing is enabled, they just are a little bit faster when compositing is disabled, which makes the movement look so much more natural.
I even doubt that it's the fault of kwin, but as I don't know better, I file this bug here.


Reproducible: Always

Steps to Reproduce:
enable/disable compositing for slower/faster scrolling



I'm using opensuse 11.4 with an intel GM 965 graphics card.

Comment 1 Roman K. 2011-04-26 18:45:36 UTC

perhaps related to bug 246084

Comment 2 Martin Flöser 2011-04-27 10:39:28 UTC

Scrolling performance is significantly improved in the OpenGL ES backend which 
will be part of 4.7

Comment 3 Martin Flöser 2011-05-22 10:58:54 UTC

I cannot notice any difference in 4.7 any more. Please try again when 4.7 is available (beta should be released in very short time) and feel free to reopen this bug if you still experience differences. In that case we need to further investigate.

As a rule of thumb: try the show paint effect if a window is constantly repainting an area.

Comment 4 Roman K. 2011-05-22 17:55:34 UTC

I will try it our when there are packages for opensuse.

Comment 5 Roman K. 2011-08-27 13:38:01 UTC

sorry for the delay, but now I have an answer:

the scrolling performance might have improved, but there still is this little delay, which gets really annoying. 

In addition to the original scrolling thing, I now noticed that this bug also appears when clicking on something (where "something" can really mean anything). Let's say I switch between windows by clicking on the entry in my window-list in my panel. With desktop effects disabled, I get to see the window instantly, without any noticeable delay. If desktop effects are enabled, I also get to see the window fast, but I would not call this instant anymore. 

I even would go further and say that all actions that have some kind of input, are not that smooth as they are when the effects are disabled. This might be keyboard input (typing very fast) or input from my mouse.

So perhaps all this is a driver problem? If you need any additional input, feel free to ask.

Comment 6 Martin Flöser 2011-12-22 10:30:47 UTC


*** This bug has been marked as a duplicate of bug 246084 ***