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Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle period

From Daniel Lezcano <daniel.lezcano@linaro.org>
Newsgroups linux.kernel
Subject Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle period
Date 2016-02-22 18:30 +0100
Message-ID <r52t5-LR-39@gated-at.bofh.it> (permalink)
References <r2Q31-1iJ-35@gated-at.bofh.it> <r2Q32-1iJ-49@gated-at.bofh.it> <r50hA-7xQ-23@gated-at.bofh.it>
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On 02/22/2016 04:02 PM, Shreyas B Prabhu wrote:
> Hi Daniel,
>
> On 02/16/2016 09:13 PM, Daniel Lezcano wrote:
>> +
>> +/**
>> + * sched_idle_next_wakeup - Predict the next wakeup on the current cpu
>> + *
>> + * The next event on the cpu is based on a statistic approach of the
>> + * interrupt events and the timer deterministic value. From the timer
>> + * or the irqs, we return the one expected to occur first.
>> + *
>> + * Returns the expected remaining idle time before being woken up by
>> + * an interruption.
>> + */
>> +s64 sched_idle_next_wakeup(void)
>> +{
>> +	s64 next_timer = ktime_to_us(tick_nohz_get_sleep_length());
>> +	s64 next_irq = next_irq_event();
>
> Since next_irq_event() uses RCU and we are in idle this should probably
> be wrapped in RCU_NONIDLE().

That is a good point but the function is not supposed to be called in 
the rcu_idle_enter/rcu_idle_exit section which is inside 
cpuidle_idle_call().


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Thread

[PATCH V3 1/2] irq: Track the interrupt timings Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-16 16:50 +0100
  [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle period Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-16 16:50 +0100
    Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-02-16 17:50 +0100
      Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle period "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-18 00:10 +0100
        Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle period "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-18 00:30 +0100
          Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-18 11:30 +0100
            Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle period "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-18 21:00 +0100
              Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-19 16:10 +0100
                Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle period "Rafael J. Wysocki" <rafael@kernel.org> - 2016-02-20 00:50 +0100
                Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-23 10:50 +0100
    Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Shreyas B Prabhu <shreyas@linux.vnet.ibm.com> - 2016-02-22 16:10 +0100
      Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-22 18:30 +0100
        Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Shreyas B Prabhu <shreyas@linux.vnet.ibm.com> - 2016-02-23 11:10 +0100
    Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Shreyas B Prabhu <shreyas@linux.vnet.ibm.com> - 2016-02-23 11:10 +0100
      Re: [PATCH V3 2/2] sched: idle: IRQ based next prediction for idle  period Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-23 11:20 +0100
  Re: [PATCH V3 1/2] irq: Track the interrupt timings Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-02-16 17:50 +0100
  Re: [PATCH V3 1/2] irq: Track the interrupt timings Shreyas B Prabhu <shreyas@linux.vnet.ibm.com> - 2016-02-22 15:50 +0100
    Re: [PATCH V3 1/2] irq: Track the interrupt timings Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-22 18:30 +0100

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