Date:   Tue, 22 Jan 2019 15:27:25 +0100
From:   Vincent Guittot <vincent.guittot@...aro.org>
To:     "open list:THERMAL" <linux-pm@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Thara Gopinath <thara.gopinath@...aro.org>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>
Subject: Re: [PATCH 2/2] PM-runtime: Replace jiffies based accounting with
 ktime-based accounting

On Tue, 22 Jan 2019 at 15:24, Vincent Guittot
<vincent.guittot@...aro.org> wrote:
>
> From: Thara Gopinath <thara.gopinath@...aro.org>
>
> This patch replaces jiffies based accounting for runtime_active_time
> and runtime_suspended_time with ktime-based accounting. This makes the
> runtime debug counters inline with genpd and other PM subsytems which
> use ktime-based accounting.
>
> Timekeeping is initialized before driver_init(). It's only at that time
> that PM runtime can be enabled.
>
> Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
> [switch from ktime to raw nsec]
> Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>

Hi Ulf,

I haven't added you reviewed-by because of the changes in this new version.

Hi Guenter,

Could you test this version ?

Thanks,
Vincent

> ---
>  drivers/base/power/runtime.c | 17 +++++++++--------
>  drivers/base/power/sysfs.c   | 11 ++++++++---
>  include/linux/pm.h           |  6 +++---
>  3 files changed, 20 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 7df1d05..e49b3a8 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -66,8 +66,8 @@ static int rpm_suspend(struct device *dev, int rpmflags);
>   */
>  void update_pm_runtime_accounting(struct device *dev)
>  {
> -       unsigned long now = jiffies;
> -       unsigned long delta;
> +       u64 now = ktime_to_ns(ktime_get());
> +       u64 delta;
>
>         delta = now - dev->power.accounting_timestamp;
>
> @@ -77,9 +77,9 @@ void update_pm_runtime_accounting(struct device *dev)
>                 return;
>
>         if (dev->power.runtime_status == RPM_SUSPENDED)
> -               dev->power.suspended_jiffies += delta;
> +               dev->power.suspended_time += delta;
>         else
> -               dev->power.active_jiffies += delta;
> +               dev->power.active_time += delta;
>  }
>
>  static void __update_runtime_status(struct device *dev, enum rpm_status status)
> @@ -90,16 +90,17 @@ static void __update_runtime_status(struct device *dev, enum rpm_status status)
>
>  u64 pm_runtime_suspended_time(struct device *dev)
>  {
> -       unsigned long flags, time;
> +       u64 time;
> +       unsigned long flags;
>
>         spin_lock_irqsave(&dev->power.lock, flags);
>
>         update_pm_runtime_accounting(dev);
> -       time = dev->power.suspended_jiffies;
> +       time = dev->power.suspended_time;
>
>         spin_unlock_irqrestore(&dev->power.lock, flags);
>
> -       return jiffies_to_nsecs(time);
> +       return time;
>  }
>  EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
>
> @@ -1308,7 +1309,7 @@ void pm_runtime_enable(struct device *dev)
>
>         /* About to enable runtime pm, set accounting_timestamp to now */
>         if (dev->power.disable_depth == 1)
> -               dev->power.accounting_timestamp = jiffies;
> +               dev->power.accounting_timestamp = ktime_to_ns(ktime_get());
>
>         if (dev->power.disable_depth > 0)
>                 dev->power.disable_depth--;
> diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
> index d713738..96c8a22 100644
> --- a/drivers/base/power/sysfs.c
> +++ b/drivers/base/power/sysfs.c
> @@ -125,9 +125,12 @@ static ssize_t runtime_active_time_show(struct device *dev,
>                                 struct device_attribute *attr, char *buf)
>  {
>         int ret;
> +       u64 tmp;
>         spin_lock_irq(&dev->power.lock);
>         update_pm_runtime_accounting(dev);
> -       ret = sprintf(buf, "%i\n", jiffies_to_msecs(dev->power.active_jiffies));
> +       tmp = dev->power.active_time;
> +       do_div(tmp, NSEC_PER_MSEC);
> +       ret = sprintf(buf, "%llu\n", tmp);
>         spin_unlock_irq(&dev->power.lock);
>         return ret;
>  }
> @@ -138,10 +141,12 @@ static ssize_t runtime_suspended_time_show(struct device *dev,
>                                 struct device_attribute *attr, char *buf)
>  {
>         int ret;
> +       u64 tmp;
>         spin_lock_irq(&dev->power.lock);
>         update_pm_runtime_accounting(dev);
> -       ret = sprintf(buf, "%i\n",
> -               jiffies_to_msecs(dev->power.suspended_jiffies));
> +       tmp = dev->power.suspended_time;
> +       do_div(tmp, NSEC_PER_MSEC);
> +       ret = sprintf(buf, "%llu\n", tmp);
>         spin_unlock_irq(&dev->power.lock);
>         return ret;
>  }
> diff --git a/include/linux/pm.h b/include/linux/pm.h
> index 0bd9de1..3d2cbf9 100644
> --- a/include/linux/pm.h
> +++ b/include/linux/pm.h
> @@ -633,9 +633,9 @@ struct dev_pm_info {
>         int                     runtime_error;
>         int                     autosuspend_delay;
>         u64                     last_busy;
> -       unsigned long           active_jiffies;
> -       unsigned long           suspended_jiffies;
> -       unsigned long           accounting_timestamp;
> +       u64                     active_time;
> +       u64                     suspended_time;
> +       u64                     accounting_timestamp;
>  #endif
>         struct pm_subsys_data   *subsys_data;  /* Owned by the subsystem. */
>         void (*set_latency_tolerance)(struct device *, s32);
> --
> 2.7.4
>

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