Re: [PATCH 5/7] thermal: stats: introduce tz time in trip

Rafael J. Wysocki
2023-06-20T17:28:46Z

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".

Doesn't this assume a specific temperature ordering of trip points?
And so what if they are not ordered?