Messages in this thread | | | Date | Thu, 15 Mar 2018 19:19:00 +0100 | From | Frederic Weisbecker <> | Subject | Re: [RFT][PATCH v4 3/7] sched: idle: Do not stop the tick before cpuidle_idle_call() |
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On Mon, Mar 12, 2018 at 10:53:25AM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Make cpuidle_idle_call() decide whether or not to stop the tick. > > First, the cpuidle_enter_s2idle() path deals with the tick (and with > the entire timekeeping for that matter) by itself and it doesn't need > the tick to be stopped beforehand.
Not sure you meant timekeeping either :)
> if (idle_should_enter_s2idle() || dev->use_deepest_state) { > if (idle_should_enter_s2idle()) { > + rcu_idle_enter(); > + > entered_state = cpuidle_enter_s2idle(drv, dev); > if (entered_state > 0) { > local_irq_enable(); > goto exit_idle; > } > + > + rcu_idle_exit(); > }
I'm not sure how the tick is stopped on suspend to idle. Perhaps through hrtimer (tick_cancel_sched_timer()) or clockevents code.
But we may have a similar problem than with idle_poll() called right after call_cpuidle(). Ie: we arrive in cpuidle_enter_s2idle() with a tick that should be reprogrammed while it is not. No idea if that can hurt somehow.
I guess it depends what happens to the tick on s2idle, I'm not clear with that.
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