Messages in this thread | | | Date | Mon, 16 Nov 2015 16:09:10 -0800 | From | Jacob Pan <> | Subject | Re: [PATCH 2/4] timer: relax tick stop in idle entry |
| |
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) { if (rq->nr_running) return 0;
Since we only take into account of cfs_rq runnable taking over cfs_rq->nr_running when forced_idle is set.
Jacob
| |