50% CPU user usage but top doesn't list any CPU unfriendly task

jerome lacoste
2005-01-03T21:46:42Z

Hi,

on a fairly old box used as a desktop (PII 300 Mhz with 196M RAM), I
observe the following strange behavior which I believe comes from the
kernel.

There's a VoIP known 'P2P' closed source application running, an IP
tables based firewall and a remote ssh session initiated. When using
top, sorting by CPU usage, no program is using more than a couple of
percent of CPU. On the other side, the total CPU user time is at
around 40%, with a 1.5 load average. Memory looks OK. The machine is
responsive as usual.

So I wonder why the cpu user time is at 40% without any particular
program showing as using CPU in the top listing. 'Problem' was
reproducible with 2.4.x and now with 2.6.8.1.

So it this a real problem or is there something that I don't
understand in particular? Thanks for the insight.

Jerome