Re: Very high CPU load when idle with 3.0-rc1

Mike Galbraith
2011-05-30T13:10:49Z

On Mon, 2011-05-30 at 13:34 +0200, Peter Zijlstra wrote:
> On Mon, 2011-05-30 at 07:59 +0200, Damien Wyart wrote:
> > Hi,
> >
> > Testing 3.0-rc1 on a core i7 (4 cores + HT), I get a load average of 9.0
> > when idle. No process is shown running or in "D state" in htop. The box
> > is behaving normal, no impression of lag or slowness.
> >
> > Not sure what other info to include, I guess this should be quite easy
> > to reproduce.
>
>
> ---
> Subject: rcu: Cure load woes
>
> Commit cc3ce5176d83 (rcu: Start RCU kthreads in TASK_INTERRUPTIBLE
> state) fudges a sleeping task' state, resulting in the scheduler seeing
> a TASK_UNINTERRUPTIBLE task going to sleep, but a TASK_INTERRUPTIBLE
> task waking up. The result is unbalanced load calculation.

(darn, 'which' poked me in the eye, but 'how' didn't)

Yup, all better.

-Mike