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SubjectRe: [PATCH v12 3/4] cpuidle: Export the next timer/tick expiration for a CPU
On 27/02/2019 20:58, Ulf Hansson wrote:
> To be able to predict the sleep duration for a CPU that is entering idle,
> knowing when the next timer/tick is going to expire, is extremely useful.
> Both the teo and the menu cpuidle governors already makes use of this
> information, while selecting an idle state.
> Moving forward, the similar prediction needs to be done, but for a group of
> idle CPUs rather than for a single idle CPU. Following changes implements a
> new genpd governor, which needs this.
> Support this, by sharing a new function called
> tick_nohz_get_next_hrtimer(), which returns the next hrtimer or the next
> tick, whatever that expires first.
> Additionally, when cpuidle is about to invoke the ->enter() callback, then
> call tick_nohz_get_next_hrtimer() and store its return value in the per CPU
> struct cpuidle_device, as to make it available outside cpuidle.
> Do note, at the point when cpuidle calls tick_nohz_get_next_hrtimer(), the
> governor's ->select() callback has already made a decision whether to stop
> the tick or not. In this way, tick_nohz_get_next_hrtimer() actually returns
> the next timer expiration, whatever origin.
> Cc: Lina Iyer <>
> Co-developed-by: Lina Iyer <>
> Co-developed-by: Daniel Lezcano <>
> Signed-off-by: Ulf Hansson <>
> ---

Acked-by: Daniel Lezcano <>

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