Re: Why is kslowd accumulating so much CPU time?

From: Andy Whitcroft
Date: Tue Jun 15 2010 - 13:25:50 EST


On Mon, Jun 14, 2010 at 10:46 PM, <tytso@xxxxxxx> wrote:
> On Mon, Jun 14, 2010 at 02:42:44PM -0400, Nick Bowler wrote:
>>
>> This sounds exactly like the issue I've been seeing on a T500 laptop, as
>> well (GM45 board).  The slowdowns render the system essentially
>> unusable, as it can spend a loooong time just moving the mouse cursor a
>> few pixels on the screen.  During this time, nothing else on the display
>> is updating (glxgears drops to 0fps).  Things generally seem to be
>> working fine if I am not moving the mouse, or if I'm not running X.
>
> I saw exactly the same behaviour when using the Ubuntu Karmic
> userspace.  Basically, using a 2.6.35-rc2 (+ vt memory corrupter fix)
> kernel, the system was essentially unusable.  Interestingly, the
> problem went away (with the same kernel) once I updated to Ubuntu
> Lucid.  I was going to mention that so that hopefully someone with far
> more X.org-fu than I could figure out how much of this is a X server
> bug, and how much of this was a kernel bug, but things worked just
> *fine* with 2.6.34 kernel.
>
> Occasionally it will happen that the mouse stops tracking, and then I
> grumble and curse, and a few seconds later it resolves itself.  I
> haven't had time to track it down; but the problem was breathtakingly
> easy to reproduce with an Ubuntu Karmic userspace.  :-)

I am seeing crunchy cursor behavior on boot on Ubuntu Lucid user space
with the 2.6.35-rc3 kernel as well. It pretty much always does that
on boot, and often later as well. Right now I have four of these
chaps each consuming 9% of a CPU. Though they definatly come and go.
Very odd:

938 root 15 -5 0 0 0 S 9 0.0 1:00.90 kslowd001
1048 root 15 -5 0 0 0 S 9 0.0 1:01.12 kslowd002
937 root 15 -5 0 0 0 S 8 0.0 1:00.92 kslowd000
1544 root 15 -5 0 0 0 D 8 0.0 1:00.55 kslowd003

-apw
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