May be off topic : System CPU usage

Punj, Arun (Arun.Punj@marconi.com)
Fri, 18 Apr 2003 15:54:10 -0400


[ Please cc: Arun.Punj@marconi.com ]

Folks

I am running into a curious problem on linux 2.4.20 kernel.

The problem :

Every 25 minutes the sytem usage as indicated by "top -i -d 1"
goes up from 0 to about 50% and stays at this level for around
100 seconds and than comes down to zero or near zero again.
The user cpu % stays at 0. And the CPU used by all the active
process put togather stays below 5%

The system is idle when this happens in so far as I can tell.
The only tasks which show up in the top are :
-- "X" and [ CPU usage ~ 5%]
-- top itself [ CPU usage ~ 0%]

The hardware configuration is as follows:
P4 2.4Ghz 512M Ram, 128M IDE compatible Flash Drive,
there is a 50 Meg CramFs parition on flash and 200 M
ext3 partition.

Could this be a kernel configuration issue.

Any help would be greatly appreciate.

thanks
Arun Punj

A snippet of what top looks like when this happens, observe the system
usage:
----------------------------------------------------------------------------

8:59am up 1 day, 22:21, 5 users, load average: 0.56, 0.49, 0.46
79 processes: 74 sleeping, 4 running, 0 zombie, 1 stopped
CPU states: 1.7% user, 48.9% system, 0.0% nice, 49.4% idle
Mem: 506380K av, 217256K used, 289124K free, 0K shrd, 15976K
buff
Swap: 0K av, 0K used, 0K free 88928K
cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
712 root 17 -1 142M 13M 2620 R < 4.9 2.7 209:28 X
7917 root 9 0 1100 1100 876 R 0.0 0.2 0:00 top

-------------------------------------------------------------------------

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