I'm running Ubuntu 10.10:

uname -a
Linux mt-xps 2.6.35-22-generic #35-Ubuntu SMP Sat Oct 16 20:45:36 UTC 2010 x86_64 GNU/Linux

When I run top, I occasionally see a "kslowd000" or similar process popping up in the top CPU usage list. I've tried googling kslowd, but found no explanation to what it is. manpages also don't help.

What does it do ? And how would I find out myself ?

2 Answers 2


It's a kernel thread performing things that typically take a lot of time. For more information, see slow-work.txt.

  • Thanks. Is there some sort of manpage or other lookup mechanism for this, or do you have to know/guess/google which daemon name is connected to which feature, and part of the Kernel or another program ?
    – Martin T.
    Nov 2, 2010 at 15:48
  • Guess, Google or just plain know. :-) OK, there are books and so on written about kernel, but they are usually very hard to read and understand. Kernel internals is not the easiest thing on Earth ... Nov 2, 2010 at 16:57
  • That's kinda disappointing, really. There's usually a lot of info for first-time users via the graphical help, and there's mind-numbing technical detail via man pages etc. But to find out concepts and which thing (program/daemon/folder/abbreviation) belongs to which other, you have to guess or ask dumb-sounding questions.
    – Martin T.
    Nov 3, 2010 at 9:01
  • Yeah. There are various sites such as kernelnewbies.org easing your journey into kernel internals, but for bigger picture the documentation lacks in many cases. Nov 3, 2010 at 10:19
  • One hint - "processes" that are listed in ps output with square brackets: [kslowd000] are usually (always?) kernel threads.
    – Dan Pritts
    Apr 29, 2013 at 21:01

To debug kslowd, you'll need to enable debugging in the kernel (and recompile is necessary) by adding to your kernel config:


Reboot, then run

watch -n0 cat /sys/kernel/debug/slow_work/runqueue

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