Re: [PATCH 13/32] nohz: Adaptive tick stop and restart on nohz cpuset

Frederic Weisbecker
2011-08-30T14:38:10Z

On Tue, Aug 30, 2011 at 02:44:10PM +0200, Peter Zijlstra wrote:
> On Mon, 2011-08-29 at 20:28 +0200, Frederic Weisbecker wrote:
> > tick_nohz_stop_sched_tick() checks that
> > with {rcu,printk,arch}_needs_cpu() and restores a periodic behaviour
> > until nobody else needs the CPU.
>
> tick_nohz_stop_sched_tick() should not restore stuff, it should at worst
> fail to stop but never enable that's just weird.

It's not really enablement, it's just nohz behaviour but the next tick is
in HZ :o)

Like you said before it's an optimization. I can do the things differently
for idle and non-idle cases there but I'm not sure it's really a good thing.