[K12OSN] CPU usage way up! What to do?

Les Mikesell les at futuresource.com
Fri Sep 10 19:26:21 UTC 2004


On Fri, 2004-09-10 at 13:41, David Trask wrote:
> When I
> show "real CPU's" then four of them show up....I'm assuming that's normal
> for a dual processor machine.

Hyperthreaded CPU's show up as 2 processors. They can run some but
not all code in parallel.

> I'd be curious to see how the 4.1 version
> with fc2 stacks up against the new WBEL version Eric posted. 

I'd be surprised if the kernel version makes much difference at all
in CPU use.  Try a 'vmstat 5' to get 5 second snapshots of cpu use.
The 'us' (user) column will be mostly from application level
processing, while the 'sy' (system) column is kernel (inside device
drivers, filesystem code, etc.).  Top should show you any single
process using a lot of CPU.  It is harder to find when 30 copies
of something are each using a chunk, and even harder when the
processes have a very short life.  You can get a feeling for how
many processes are starting by typeing 'ps', noting the process id
of the ps process itself, then repeating in a few seconds.  If the
number jumps by hundreds each time you have something odd happening.

---
  Les Mikesell
   les at futuresource.com






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