linux-kernel - Re: [PATCH 2/2] PM-runtime: update time accounting only when enabled

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Date:   Tue, 5 Feb 2019 09:09:54 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Biju Das <biju.das@...renesas.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Thara Gopinath <thara.gopinath@...aro.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH 2/2] PM-runtime: update time accounting only when enabled

On Mon, 4 Feb 2019 at 17:26, Vincent Guittot <vincent.guittot@...aro.org> wrote:
>
> Update accounting_timestamp field only when PM runtime is enable
> and don't forget to account the last state before disabling it.
>
> Suggested-by: Ulf Hansson <ulf.hansson@...aro.org>
> Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>

Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

Kind regards
Uffe


> ---
>  drivers/base/power/runtime.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 50740da..ed62cca 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -66,11 +66,14 @@ static int rpm_suspend(struct device *dev, int rpmflags);
>   */
>  void update_pm_runtime_accounting(struct device *dev)
>  {
> -       u64 now = ktime_get_mono_fast_ns();
> -       u64 last = dev->power.accounting_timestamp;
> -       u64 delta;
> +       u64 now, last, delta;
>
> -       dev->power.accounting_timestamp = now;
> +       if (dev->power.disable_depth > 0)
> +               return;
> +
> +       last = dev->power.accounting_timestamp;
> +
> +       dev->power.accounting_timestamp = now = ktime_get_mono_fast_ns();
>
>         /*
>          * Because ktime_get_mono_fast_ns() is not monotonic during
> @@ -82,9 +85,6 @@ void update_pm_runtime_accounting(struct device *dev)
>
>         delta = now - last;
>
> -       if (dev->power.disable_depth > 0)
> -               return;
> -
>         if (dev->power.runtime_status == RPM_SUSPENDED)
>                 dev->power.suspended_time += delta;
>         else
> @@ -1298,6 +1298,9 @@ void __pm_runtime_disable(struct device *dev, bool check_resume)
>                 pm_runtime_put_noidle(dev);
>         }
>
> +       /* Update time accounting before disabling pm runtime */
> +       update_pm_runtime_accounting(dev);
> +
>         if (!dev->power.disable_depth++)
>                 __pm_runtime_barrier(dev);
>
> @@ -1521,7 +1524,6 @@ void pm_runtime_init(struct device *dev)
>         dev->power.request_pending = false;
>         dev->power.request = RPM_REQ_NONE;
>         dev->power.deferred_resume = false;
> -       dev->power.accounting_timestamp = 0;
>         INIT_WORK(&dev->power.work, pm_runtime_work);
>
>         dev->power.timer_expires = 0;
> --
> 2.7.4
>