Re: CONFIG_NO_HZ_FULL + CONFIG_PREEMPT_RT_FULL = nogo

From: Mike Galbraith
Date: Sun Dec 22 2013 - 00:16:36 EST


On Sun, 2013-12-22 at 05:17 +0100, Mike Galbraith wrote:
> On Sat, 2013-12-21 at 19:21 +0200, Muli Baron wrote:
> > On 21/12/2013 11:11, Mike Galbraith wrote:
> > >
> > > Works, modulo noisy workqueues.
> > >
> > > rtbox:~ # sleep 35 && killall pert& cgexec -g cpuset:rtcpus taskset -c 3 pert 5
> > > [1] 5660
> > > 2400.05 MHZ CPU
> > > perturbation threshold 0.018 usecs.
> > > pert/s: 33 >15.75us: 2 min: 0.04 max: 24.14 avg: 2.51 sum/s: 84us overhead: 0.01%
> > > pert/s: 35 >15.54us: 3 min: 0.04 max: 24.89 avg: 2.39 sum/s: 84us overhead: 0.01%
> > > pert/s: 30 >15.27us: 2 min: 0.04 max: 23.03 avg: 2.64 sum/s: 80us overhead: 0.01%
> > > pert/s: 34 >15.12us: 3 min: 0.04 max: 25.03 avg: 2.51 sum/s: 86us overhead: 0.01%
> > > pert/s: 31 >14.93us: 2 min: 0.04 max: 23.86 avg: 2.60 sum/s: 83us overhead: 0.01%
> > > Terminated
> > >
> >
> > I can confirm this works for me as well, but I have noticed some strange behavior under certain
> > conditions.
>
> Hm, so can I. Same everything, different day, nohz_full is NOT working.

But while I was off futzing with DL980, it started working all by
itself, after not working _at all_ for three reboot/play attempts.

There's a phase-of-moon bug lurking in there somewhere.

-Mike


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