asterisk users - Dec 2013 - High load on asterisk servers

I have a problem with asterisk. I got ~15 asterisk servers on new 
hardware (1 or 2 xeon 3ghz) sometimes I got high load between 1 and 10. 
No disk activity, no ram or swap problem. But asterisk main process is 
using up to 300-500% cpu. This happens both with 30 channels in use and 
100+ channels in use. I'm not doing transcoding or anything. any clue ?

One server with 300 channels load on 5
One server with 600 channels load on 0.02

After 5 minutes it might be ok... some times its ok after 1 hour.

I do no recording, no transcoding just g711a

Two servers does not have sip-registrations as they are gateways to our 
sip-propvider. The other servers got around 1000-1200 sip registrations.

Running asterisk 11.5.x, 11.6.0 and now trying 11.7.0

All servers HP with centos 6.5 (has been 6.3 and 6.4 as well)

Any clue ?

/Henrik

Am 19.12.2013 10:37, schrieb Henrik Andresen:
> I have a problem with asterisk. I got ~15 asterisk servers on new 
> hardware (1 or 2 xeon 3ghz) sometimes I got high load between 1 and 
> 10. No disk activity, no ram or swap problem. But asterisk main 
> process is using up to 300-500% cpu. This happens both with 30 
> channels in use and 100+ channels in use. I'm not doing transcoding or 
> anything. any clue ?
>
> One server with 300 channels load on 5
> One server with 600 channels load on 0.02
>
> After 5 minutes it might be ok... some times its ok after 1 hour.
>
> I do no recording, no transcoding just g711a
>
> Two servers does not have sip-registrations as they are gateways to 
> our sip-propvider. The other servers got around 1000-1200 sip 
> registrations.
>
> Running asterisk 11.5.x, 11.6.0 and now trying 11.7.0
>
> All servers HP with centos 6.5 (has been 6.3 and 6.4 as well)
>
> Any clue ?
>
> /Henrik 
What calls cause these problems? SIP or E1/T1-Calls?