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From:   Vincent Guittot <vincent.guittot@linaro.org>
Date:   Wed, 6 Nov 2019 09:32:16 +0100
Message-ID: <CAKfTPtBrOdiN+wBfy-1cHr65d48-cBZc3LS7Jt_65Ptssb0Gpg@mail.gmail.com>
Subject: Re: [Patch v5 3/6] sched/fair: Enable periodic update of average
 thermal pressure
To:     Thara Gopinath <thara.gopinath@linaro.org>
Cc:     Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ionela Voinescu <ionela.voinescu@arm.com>,
        Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>,
        Quentin Perret <qperret@google.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Amit Kachhap <amit.kachhap@gmail.com>,
        Javi Merino <javi.merino@kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On Tue, 5 Nov 2019 at 19:49, Thara Gopinath <thara.gopinath@linaro.org> wrote:
>
> Introduce support in CFS periodic tick and other bookkeeping apis
> to trigger the process of computing average thermal pressure for a
> cpu. Also consider avg_thermal.load_avg in others_have_blocked
> which allows for decay of pelt signals.
>
> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> ---
>
> v4->v5:
>         - Updated both versions of update_blocked_averages to trigger the
>           process of computing average thermal pressure.
>         - Updated others_have_blocked to considerd avg_thermal.load_avg.
>
>  kernel/sched/fair.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 2e907cc..9fb0494 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -92,6 +92,8 @@ const_debug unsigned int sysctl_sched_migration_cost  = 500000UL;
>   */
>  static DEFINE_PER_CPU(unsigned long, thermal_pressure);
>
> +static void trigger_thermal_pressure_average(struct rq *rq);
> +
>  #ifdef CONFIG_SMP
>  /*
>   * For asym packing, by default the lower numbered CPU has higher priority.
> @@ -7493,6 +7495,9 @@ static inline bool others_have_blocked(struct rq *rq)
>         if (READ_ONCE(rq->avg_dl.util_avg))
>                 return true;
>
> +       if (READ_ONCE(rq->avg_thermal.load_avg))
> +               return true;
> +
>  #ifdef CONFIG_HAVE_SCHED_AVG_IRQ
>         if (READ_ONCE(rq->avg_irq.util_avg))
>                 return true;
> @@ -7580,6 +7585,8 @@ static void update_blocked_averages(int cpu)
>                 done = false;
>
>         update_blocked_load_status(rq, !done);
> +
> +       trigger_thermal_pressure_average(rq);

This must be called before others_have_blocked() to take into account
the latest update

>         rq_unlock_irqrestore(rq, &rf);
>  }
>
> @@ -7646,6 +7653,7 @@ static inline void update_blocked_averages(int cpu)
>         update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
>         update_irq_load_avg(rq, 0);
>         update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq));
> +       trigger_thermal_pressure_average(rq);

idem

>         rq_unlock_irqrestore(rq, &rf);
>  }
>
> @@ -9939,6 +9947,8 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
>
>         update_misfit_status(curr, rq);
>         update_overutilized_status(task_rq(curr));
> +

remove blank line

> +       trigger_thermal_pressure_average(rq);
>  }
>
>  /*
> --
> 2.1.4
>