Re: System load of 1 with CPU 100% idle

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Jun 29, 2011 at 06:27:41PM +0200, Roger Pau Monné wrote:
> Hello,
> 
> I'm seeing some strange behaviour in a NetBSD installation with
> RAIDframe, the load of the system goes to 1 with no reason, an then
> goes to 0 again after a period of time (usually after some hours). The
> output of the "top" command is the following:
> 
> [...]
> System is always in "raidiow" state, but at the same time CPU is
> always 100% idle, so I don't know how I have an average load of 1 if
> the CPU is not used. I have another system, with the same hardware and
> configuration (except for the software disk RAID) that is reporting
> load as expected, and is also running a Xen Dom0, so it makes me thing
> it has something to do with the software RAID. Could someone provide
> and explanation of what's happening?

load is more than just a function of CPU usage; for example I/O is also
used in computation. If there a parity rewrite running when this happens ?
If so, the load could be related to I/O generated by this ...

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--