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Old 01-31-2007, 04:49 AM   #1
Registered: Dec 2004
Location: Trondheim, Norway
Distribution: kubuntu 10.04
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source of high cpu usage

a few minutes ago my system was very slow, because the cpu was very busy, but I could not figure out with what.

'top' had a cpu usage line looked someting like this: (reconstructed)
Cpu(s):  3.4% us,  10.7% sy,  1.0% ni, 2.2% id,  0.0% wa,  10.3% hi,  72.7% si
here the last field, "si" was fluctuating between 40% and 90%, almost nothing in idle or user, making it hard to find what was so complicated to process.

edit: clarify problem.
What do the different fields mean: my guess is 'us'=userspace(or something similar, running programs) 'sy'=system(kernel level), 'id'=idle.
the others I do not know. what are they, is it possible to trace where cpu power allocated to them is going, and maybe reduce them, if too much is going there, bogging down the system.

Last edited by edgjerp; 01-31-2007 at 07:22 AM.
Old 01-31-2007, 09:57 PM   #2
Registered: Nov 2004
Location: ON, CANADA
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'si' is software interrupts.
man top
for more details on the fields.
Old 01-31-2007, 10:31 PM   #3
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Location: Brisbane, Australia
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While you're reading the man page...

Have a look at the -b and -n options. You can have top run once and dump its output to a file so you can check the data afterwards and post it here (if necessary).
top -b -n 1 > /tmp/top.log
Old 01-31-2007, 10:38 PM   #4
Registered: Jun 2004
Location: Wantage, NJ
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If you have X running with Gnome or KDE (Gnome is better ), just load up gnome-system-monitor. That'll tell ya pretty much all you need to know...
Old 02-02-2007, 03:37 AM   #5
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You'll be guessing, but it's likely the highest CPU consumer is generating all those interrupts.
Sounds like something gone feral.


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