CentOS - Jan 2010 - High load since passing from rhas3 to centos4.8

We are migrating HP servers from RHAS3 to centos 4.8. Since, the load average is
reaching really high values. Under usage we see loads of 15-20 instead of the
0.5-1.5 we were used to.
I searched a lot for information on such an issue. Iostat, vmstat, top, ps. But
I don't get significant hint.
Cpu usage remains low, IO wait remains low, no disks are lagging, no swap usage.

Are there some tool / other way to diagnose why the load average is high? Like
which processes are waiting, where they are stuck. Are there calls to drivers or
system process that are slow?

Thanks
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On Thu, Jan 14, 2010 at 2:12 PM,  <fortin.pierre at bell.ca>
wrote:
> We are migrating HP servers from RHAS3 to centos 4.8. Since, the load
> average is reaching really high values. Under usage we see loads of 15-20
> instead of the 0.5-1.5 we were used to.
>
> I searched a lot for information on such an issue. Iostat, vmstat, top, ps.
> But I don?t get significant hint.
>
> Cpu usage remains low, IO wait remains low, no disks are lagging, no swap
> usage.
>
>
>
> Are there some tool / other way to diagnose why the load average is high?
> Like which processes are waiting, where they are stuck. Are there calls to
> drivers or system process that are slow?
Are you by any chance now running a CPU throttling program and weren't
before?

On 1/14/2010 1:12 PM, fortin.pierre at bell.ca wrote:
> We are migrating HP servers from RHAS3 to centos 4.8. Since, the load
> average is reaching really high values. Under usage we see loads of
> 15-20 instead of the 0.5-1.5 we were used to.
>
> I searched a lot for information on such an issue. Iostat, vmstat, top,
> ps. But I don?t get significant hint.
>
> Cpu usage remains low, IO wait remains low, no disks are lagging, no
> swap usage.
>
> Are there some tool / other way to diagnose why the load average is
> high? Like which processes are waiting, where they are stuck. Are there
> calls to drivers or system process that are slow?
I don't have an answer but out of curiosity, why would you move to a 4.x 
instead of 5.x now?

You might be able to do some ps snapshots to see the process in R state, 
which is what the load average should be counting.  That might be 
computed differently between the 2.4 and 2.6 kernels.

-- 
   Les Mikesell
    lesmikesell at gmail.com