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#1 2013-11-16 19:39:14

SeeLook
Member
Registered: 2012-07-01
Posts: 19

[SOLVED] Kwin in multisession takes 100% CPU

Hi!
I dared to put this topic because I can't find workaround anywhere

When I'm opening second session, kwin sucks 100% for first user kwin process,
when I'm switching back (ctrl+alt+F7) to first session, it starts the same for second user.
It stops when I switched off KDE desktop effects.
I tried to add users to 'video' group - doesn't help

It has happened for a month or bit more and before never occured.
I'm using nvidia-304 for GForce 6150 on-board staff.

Can you help me?

Last edited by SeeLook (2013-12-14 19:00:30)

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#2 2013-11-20 08:42:48

bhrgunatha
Member
Registered: 2009-12-16
Posts: 101

Re: [SOLVED] Kwin in multisession takes 100% CPU

I think I have the same problem, but the behaviour is a little different.

When rebooting once kdm starts if I log in to the terminal (CTRL+ALT+F1) and run htop there are 3 kwin processes 2 with the same session id and a third which is always pegged at 100% CPU.

Of I go back to KDE (CTRL+ALT+F7) and run htop there - same again - 3 kwin processes - but they all have normal CPU usage (below 5% for example)

Same as you this has been there for a while.

There is a further strange issue I've noticed more recently - there are a bunch of zombie kwin_opengl_tes processes reported (this tie by KDE System monitor)

Why are they zombie processes?
Should I be worried about them?

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#3 2013-11-20 09:01:36

bhrgunatha
Member
Registered: 2009-12-16
Posts: 101

Re: [SOLVED] Kwin in multisession takes 100% CPU

OK - so after a reboot. There is a single kwin process and no zombies.

However from the startup terminal it is still reporting 100% CPU usage and from within KDE it is reported at normal low CPU usage.

$ uname -srv
Linux 3.12.0-1-ARCH #1 SMP PREEMPT Wed Nov 6 09:06:27 CET 2013

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#4 2013-12-13 05:23:03

awesomesatan
Member
Registered: 2013-12-13
Posts: 5

Re: [SOLVED] Kwin in multisession takes 100% CPU

Switching the compositing type, in the advanced section of desktop effects, to XRender seems to at least be a workaround for this issue for me. I get a message that two effects could not be started, so not optimal, but at least no more cpu spike.

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#5 2013-12-13 11:36:44

SeeLook
Member
Registered: 2012-07-01
Posts: 19

Re: [SOLVED] Kwin in multisession takes 100% CPU

Thanks for response and for the clue.

It is really working but unfortunately those two effects are my favourite ones....
(cube desktop switch and windows covers switch)

So far my workaround is to switch off effects when I'm changing session screen.
I have already a habit to do this :-(
Fortunately it is necessary only first two times after boot and resume from suspend. After that the effects can be switched on. Because my uptime-s are quite long (1-2 weeks) it is not so painfully...

Anyway I'm considering to buy new graphics card (mostly because the current one is slow) to be able of using newest drivers.
Can you confirm that this issue is related to nVidia-304 drivers?
I didn't meet this issue on AMD catalyst-s/radeon-s

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#6 2013-12-13 16:18:44

awesomesatan
Member
Registered: 2013-12-13
Posts: 5

Re: [SOLVED] Kwin in multisession takes 100% CPU

I am using the latest nVidia drivers 331.20-2. I experienced the same issue on openSUSE 13.1.

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#7 2013-12-13 16:39:46

awesomesatan
Member
Registered: 2013-12-13
Posts: 5

Re: [SOLVED] Kwin in multisession takes 100% CPU

The system having issue has a GeForce GT 640. I was just testing on my laptop which has a NVS 4200M, and it does not have the same issue. Both systems are using the latest drivers. I found this https://bbs.archlinux.org/viewtopic.php?id=169743 will check later to see if this issue may be related.

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#8 2013-12-13 18:58:33

awesomesatan
Member
Registered: 2013-12-13
Posts: 5

Re: [SOLVED] Kwin in multisession takes 100% CPU

Just tested, so far so good.

I created /etc/profile.d/00-glyield.sh containing

export __GL_YIELD="USLEEP"

and made it executable. I also added /etx/X11/xorg.conf.d/20-nvidia.conf containing

Section "Device" Identifier "GeForce GTX 640" 
 Driver "nvidia" 
 Option "NoLogo" "True" 
 Option "CoolBits" "1" 
 Option "TripleBuffer" "True" 
EndSection

Seems to make initial login take even longer, but things seem to work after. The kde bug linked from the aforementioned post was were I got the settings from and has a better explanation https://bugs.kde.org/show_bug.cgi?id=322060.

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#9 2013-12-14 18:59:59

SeeLook
Member
Registered: 2012-07-01
Posts: 19

Re: [SOLVED] Kwin in multisession takes 100% CPU

Thanks a lot.

It works for me as well.
I tortured two KDE sessions with wild switching, locking  and nothing....
CPU cores are boring now as such as lazy dogs.

All the best for all Archers!

Last edited by SeeLook (2013-12-14 19:01:27)

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