Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230519032719.2581689-1-evalenti@kernel.org> <20230519032719.2581689-6-evalenti@kernel.org>
 <CAJZ5v0hho1B6TiwshT4kYhs+Z4Q6xvnbgf8aoEZop=owkJHqxg@mail.gmail.com> <ZJKAYAx5768atJa8@uf8f119305bce5e.ant.amazon.com>
In-Reply-To: <ZJKAYAx5768atJa8@uf8f119305bce5e.ant.amazon.com>
From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Fri, 23 Jun 2023 18:40:20 +0200
Message-ID: <CAJZ5v0jVL69QYpUFCMBeZ9eACca4XoeR6Js_qoDd2K5PfU9BwA@mail.gmail.com>
Subject: Re: [PATCH 5/7] thermal: stats: introduce tz time in trip
To:     Eduardo Valentin <evalenti@kernel.org>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>, eduval@amazon.com,
        linux-pm@vger.kernel.org,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Amit Kucheria <amitk@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Precedence: bulk

On Wed, Jun 21, 2023 at 6:45 AM Eduardo Valentin <evalenti@kernel.org> wrote:
>
> On Tue, Jun 20, 2023 at 07:27:57PM +0200, Rafael J. Wysocki wrote:
> >
> >
> >
> > On Fri, May 19, 2023 at 5:27 AM Eduardo Valentin <evalenti@kernel.org> wrote:
> > >
> > > From: Eduardo Valentin <eduval@amazon.com>
> > >
> > > This patch adds a statistic to report how long
> > > the thermal zone spent on temperature intervals
> > > created by each trip point. The first interval
> > > is the range below the first trip point. All
> > > subsequent intervals are accounted when temperature
> > > is above the trip point temperature value.
> > >
> > > Samples:
> > > $ cat /sys//class/thermal/thermal_zone0/stats/time_in_trip_ms
> > > trip-1  0       0
> >
> > The above line is confusing.
> >
> > > trip0   -10000  35188
> > > trip1   25000   0
> >
> > And the format violates the "one value per attribute" sysfs rule.
> >
> > > $ cat /sys//class/thermal/thermal_zone0/stats/time_in_trip_ms
> > > trip-1  0       0
> > > trip0   -10000  36901
> > > trip1   25000   0
> > > $ echo 25001 > /sys//class/thermal/thermal_zone0/emul_temp
> > > $ cat /sys//class/thermal/thermal_zone0/stats/time_in_trip_ms
> > > trip-1  0       0
> > > trip0   -10000  47810
> > > trip1   25000   2259
> > > $ cat /sys//class/thermal/thermal_zone0/stats/time_in_trip_ms
> > > trip-1  0       0
> > > trip0   -10000  47810
> > > trip1   25000   3224
> > > $ echo 24001 > /sys//class/thermal/thermal_zone0/emul_temp
> > > $ cat /sys//class/thermal/thermal_zone0/stats/time_in_trip_ms
> > > trip-1  0       0
> > > trip0   -10000  48960
> > > trip1   25000   10080
> > > $ cat /sys//class/thermal/thermal_zone0/stats/time_in_trip_ms
> > > trip-1  0       0
> > > trip0   -10000  49844
> > > trip1   25000   10080
> > >
> > > Cc: "Rafael J. Wysocki" <rafael@kernel.org> (supporter:THERMAL)
> > > Cc: Daniel Lezcano <daniel.lezcano@linaro.org> (supporter:THERMAL)
> > > Cc: Amit Kucheria <amitk@kernel.org> (reviewer:THERMAL)
> > > Cc: Zhang Rui <rui.zhang@intel.com> (reviewer:THERMAL)
> > > Cc: Jonathan Corbet <corbet@lwn.net> (maintainer:DOCUMENTATION)
> > > Cc: linux-pm@vger.kernel.org (open list:THERMAL)
> > > Cc: linux-doc@vger.kernel.org (open list:DOCUMENTATION)
> > > Cc: linux-kernel@vger.kernel.org (open list)
> > >
> > > Signed-off-by: Eduardo Valentin <eduval@amazon.com>
> > > ---
> > >  .../driver-api/thermal/sysfs-api.rst          |  2 +
> > >  drivers/thermal/thermal_sysfs.c               | 86 +++++++++++++++++++
> > >  2 files changed, 88 insertions(+)
> > >
> > > diff --git a/Documentation/driver-api/thermal/sysfs-api.rst b/Documentation/driver-api/thermal/sysfs-api.rst
> > > index ed5e6ba4e0d7..4a2b92a7488c 100644
> > > --- a/Documentation/driver-api/thermal/sysfs-api.rst
> > > +++ b/Documentation/driver-api/thermal/sysfs-api.rst
> > > @@ -359,6 +359,8 @@ Thermal zone device sys I/F, created once it's registered::
> > >      |---stats/reset_tz_stats:  Writes to this file resets the statistics.
> > >      |---stats/max_gradient:    The maximum recorded dT/dt in uC/ms.
> > >      |---stats/min_gradient:    The minimum recorded dT/dt in uC/ms.
> > > +    |---stats/time_in_trip_ms: Time spent on each temperature interval of
> > > +                               trip points.
> >
> > I would write "in each temperature interval between consecutive trip points".
>
> Ok
>
> >
> > Doesn't this assume a specific temperature ordering of trip points?
> > And so what if they are not ordered?
>
> It does. I believe other things will break if they are not ordered.

But there's no guarantee that they will be ordered, so it looks like
those other things are already broken.