Different performance with different user accounts?

[Ancoron Luciferis]

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Michel Dänzer wrote:
> On Thu, 2009-12-10 at 00:45 +0100, Ancoron Luciferis wrote: 
>> I have a machine with two user accounts under Kubuntu 9.10 and the
>> performance difference I am experiencing is measurable. The first user
>> account (set up during installation time) works good. Glxgears is around
>> 4000 FPS, video playback is fine, compositing is fine (especially the
>> desktop cube is fast as hell and really smooth).
>>
>> On the other hand there is a second user account (this one is not in the
>> admin group but basic setup is the same). In that user account I get
>> only around 2700 FPS, compositing works fine (the cube is still that
>> fast) but moving windows around is dead slow and video playback is NOT
>> "tear-free". The rather strange thing is that it doesn't depend on video
>> source frame size or codec or scaled frame size, the playback is just
>> dropping frames especially when there is a lot of movement.
>>
>> Turning off the compositing results in a fast user experience but since
>> it is fast with compositing for the first user I expected it to be the
>> same for the second one.
>>
>> CPU usage is not the problem as the quad-core machine is idling around
>> between 70% and 90% although Xorg is between 30 and 50% and mplayer
>> between 1% and 26% (peeks up to 47%) when watching a movie.
>>
>> System:
>> - - AMD Athlon II X4 620
>> - - 4GB RAM
>> - - Radeon X1950XTX
>> - - Dell 3007WFP-HC 30" @ 2560x1600
>>
>> This doesn't make sense for me at all.
>>
>> Can someone shed some light on this?
> 
> Have you tried comparing e.g. the glxinfo output between the two
> accounts?
> 
> 

'glxinfo -v' yields the exact same results under both user accounts.

I found out what caused the dramatic performance lag: amor

The second user is running the small cat 'neko'. When disabled, the user
experience is the same as it is with the first user.

glxgears with amor running:
13931 frames in 5.0 seconds = 2786.095 FPS
13475 frames in 5.0 seconds = 2694.940 FPS
13110 frames in 5.0 seconds = 2616.737 FPS
13515 frames in 5.0 seconds = 2702.943 FPS
16012 frames in 5.0 seconds = 3202.190 FPS
14027 frames in 5.0 seconds = 2795.201 FPS
15920 frames in 5.0 seconds = 3180.834 FPS
13449 frames in 5.0 seconds = 2689.747 FPS

glxgears without amor:
19291 frames in 5.0 seconds = 3858.148 FPS
20093 frames in 5.0 seconds = 4018.454 FPS
20013 frames in 5.0 seconds = 4002.501 FPS
20895 frames in 5.0 seconds = 4178.815 FPS
20834 frames in 5.0 seconds = 4166.731 FPS
20168 frames in 5.0 seconds = 4033.281 FPS
20572 frames in 5.0 seconds = 4114.335 FPS
20308 frames in 5.0 seconds = 4061.359 FPS

Also the video playback is smooth as it should be (even with 1920x1080
content) and moving windows around is as fast as with the first user
account.

But this is still a bit strange to me, as the CPU usage for that amor is
nearly 0% all the time. So it must somehow interfere the rendering
pipeline. Could this still be an issue in the driver?


Thanx,

Ancoron






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