Re: [PATCH 2/4] timer: relax tick stop in idle entry

Peter Zijlstra
2015-11-19T19:06:37Z

On Mon, Nov 16, 2015 at 04:09:10PM -0800, Jacob Pan wrote:
> On Mon, 16 Nov 2015 23:01:12 +0100 (CET)
> Thomas Gleixner <tglx@linutronix.de> wrote:
>
> > > For the second case, which is much more rare, I think we do have
> > > next timer exactly one tick away. Just don't know why tick will
> > > continue into idle loop.
> >
> > Well, it should not be hard to figure that out. There are not so many
> > checks involved when tick_nohz_irq_exit() is called.

> Thanks for the tip, I found the cause is in
> int idle_cpu(int cpu)

Which one? That is, I cannot find a idle_cpu() call from
tick_nohz_irq_exit().