Hiya I'm sort of having a question concerning the blur effect introduced in KDE SC 4.5.

Problem (Blur effect enabled):
Kwin is eating up 10-12% of my CPU and about 100 MiBs of memory when Blur is enabled, one window opened not even moving the mouse.
Also the X server is slowly eating up more and more memory over time and the whole system becoming more and more unresponsive (for obvious reasons). Also CPU workload bouncing back and forth between the two.

Blur effect disabled:
Xorg hovering between 60-70 Mibs as opposed to 256+ and increasing
Kwin not even registering any CPU load using approx. 20 Mibs

System:
Archlinux with x86_64 Kernel 2.6.35.1
Xorg 1.8.1.902-1
KDE SC 4.5 (from testing)
NVidia Geforce 6600 GT 256 memory (256.44-2)
AMD Athlon 64 3200+ (Single Core)
2 Gigs of RAM

Deactivating the effect didn't release any resources (I might have been too impatient here though). I killed the X ^^

Is this behavior to be expected on my system?

It's difficult to say, if it is expected, but your graphicscard is rather old and I doubt that the new drivers improve the performance for this model. If the effect causes problems for you, just disable it

That's the first thing I did as it became nearly impossible after a while to operate my PC.

I'll post updates if I find a(n easy) solution for my problem ^^

I got the same issues on Kubuntu Lucid after upgrading to KDE 4.5 via ppa. CPU usage with xorg would spike up to 30% on my dual XEON. I turned off blur and everything is back to normal. I have a nvidia 8400GS graphic card with latest nvidia driver installed via x ppa.

I had the same problem -- upgraded openSUSE to 11.3, and the desktop was crawling (5-15 FPS, kwin took 90% of CPU time). I had already settled with falling back to XRender, but then I noted that blur had been introduced with KDE 4.5. Disabling blur fixed the issue: I'm back at 60 FPS.

I have nVidia 9600 GT with latest proprietary drivers, so I kind of doubt that it would be a problem of insufficient hardware.

Having played around a bit trying different things I've made a few discoveries:

If the system begins to act up because of described problem restarting the plasma-desktop fixed the problem for this session.

To stop

Code: Select all

kquitapp plasma-desktop

and to restart:

Code: Select all

plasma-desktop

either in krunner or konsole.

A more permanent cure was by removing the configuration files and starting from a vanilla KDE 4 configuration.
I can now even use the blur effects even with my dated hardware. kwin is still jumping between 5-11% cpu but the system is by far more responsive and is not eating away on my memory any longer. - This far anyway ^^

I had this problem with the blur effect as well, although my graphic card is not exactly what I may call good, it's an NVidia 6150 or something like that. Disabling the blur effect fixed the slowness, restarting plasma-desktop did not help.

blur effect really blurs the kde image (pun intended)

it's is really slowing kde and os down by consuming huge cpu time.

with blur disabled kwin may use 1-2% cpu usage,

but with blur on, everything starts to become blurry 10-30% cpu usage... kwin needs to fix the blurred algorithm...

In most cases, this is due to the Graphics Driver in use suffering from poor performance with the methods that KWin uses. This is especially the case with current Intel drivers.

Unfortunately the only drivers which can be considered relatively better are from nvidia and most of these blur issues persist with it sadly.

I have tried on two comps with Open Suse 11.4 x 64, KDE 4.6 and NVidia proprietary drivers 270.41.19 KWIN and Compiz. One comps has Nvidia Geforce 6150 and monitor 1024x768, the other Geforce 8300 and monitor 1920x1080. The first one works much more smoothly with kwin. In case of compiz both works fine.
I an not agree that older NVidia cards are the main problem and the NVidia drivers are that bad. Then how compiz manages to make nearly the same desktop effects on the same hardware with the same drivers using times less CPU power?
Compiz blur does not affect CPU usage on playing video , kwin does. Compiz Blur does not leave artifacts on rolling window, kwin leaves blur behind the rolled or hovered window. Obviously the code or the approach in kwin blur needs of clearing or fixing.
For example on a audio call the sip client use 4-5 % CPU , kwin jumps to 20 % and Xorg takes another 38 % , switching off the desktop effect keeps kwin at 0 % and xorg at 3-8% . If compiz is composite manager - there is Xorg around 10 % and compiz around 5 %.
I used to use compiz manager in KDE4 , but in KDE 4.6 that actually is imposible for some reason.

Some versions of the NVidia driver, especially the newer ones in the 270 series are known to contain regressions which severely penalise the performance and operation of KWin.

bcooksley wrote:Some versions of the NVidia driver, especially the newer ones in the 270 series are known to contain regressions which severely penalize the performance and operation of KWin.

Actually the performance and stability has increased since I had upgraded with 270 series drivers. The blur is the one affects performance lots of, switching it off the system becomes more light and quick. There is hope that will be improved in 4.7.
But then again I wonder how compiz manages to run all the desktop eye candies lightly and smoothly using the same drivers. Compiz offers to blur the moving objects and blured moving windows hasn't increased the cpu usage more then 5 % . If kwin does that the system will freeze.
I admire the better integrity of desktop effects in kwin and I lack the great variety of effects compiz offers.

The performance difference is due to the difference in techniques used by KWin and Compiz. I believe Compiz uses hand-coded GL commands, which may differ depending on the driver in use, whilst KWin uses shaders and other OpenGL commands, which Mesa then converts for use by the driver.

The proprietary Nvidia and Ati drivers contain their own versions of Mesa.

In regards to improving performance, I'm not sure where to start unfortunately. There is a posting on the forum here containing a list of X configuration items which improve Nvidia performance. Not sure if that is still relevant now however.

The OpenSuse runs Nuoveau automatically on installation, but it doesn't support all of the desktop effects. So there is no alternative for the moment of Nvidea driver.
I am wandering how developers write all of the desktop effects if they are not written according proprietary drivers, the open source ones doesn't run all of the effects ?