Mysql high cpu usage problem

[vikki saggu]

Hi,

I have a linux server with apache+php+mysql.

I have two 2.8 Ghz Xeon CPU's. Hyperthreading is enabled. 2 gigs of RAM.
machdep.hlt_logical_cpus=0 and polling is enabled.

Mysql (which was compiled with linux_threads and staticly linked libraries)
has started to consume lots of cpu time (mainly system and nice times)

Here's a moment from top output:
last pid: 60888; load averages: 114.70, 114.42, 115.72
up 2+01:10:28 10:44:18
3 processes: 2 running, 1 sleeping
CPU states: 1.7% user, 52.3% nice, 44.9% system, 1.1% interrupt, 0.0%
idle
Mem: 494M Active, 1034M Inact, 357M Wired, 97M Cache, 199M Buf, 21M Free
Swap: 3072M Total, 104K Used, 3072M Free

What's worth attention here is that, cpu spends nearly all of its time
in kernel mode.

Number of hits, the web server gets did not change much, maybe a little
rise.

Can you please provide some info tracking down the problem?