Re: [PATCH v1 1/3] thermal/debugfs: Avoid excessive updates of trip point statistics

Lukasz Luba
2024-04-22T11:14:49Z

On 4/17/24 14:09, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Since thermal_debug_update_temp() is called before invoking
> thermal_debug_tz_trip_down() for the trips that were crossed by the
> zone temperature on the way up, it updates the statistics for them
> as though the current zone temperature was above the low temperature
> of each of them. However, if a given trip has just been crossed on the
> way down, the zone temperature is in fact below its low temperature,
> but this is handled by thermal_debug_tz_trip_down() running after the
> update of the trip statistics.
>
> The remedy is to call thermal_debug_update_temp() after
> thermal_debug_tz_trip_down() has been invoked for all of the
> trips in question, but then thermal_debug_tz_trip_up() needs to
> be adjusted, so it does not update the statistics for the trips
> that has just been crossed on the way up, as that will be taken
> care of by thermal_debug_update_temp() down the road.
>
> Modify the code accordingly.
>
> Fixes: 7ef01f228c9f ("thermal/debugfs: Add thermal debugfs information for mitigation episodes")
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/thermal/thermal_core.c | 3 ++-
> drivers/thermal/thermal_debugfs.c | 7 -------
> 2 files changed, 2 insertions(+), 8 deletions(-)
>
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -427,7 +427,6 @@ static void update_temperature(struct th
> trace_thermal_temperature(tz);
>
> thermal_genl_sampling_temp(tz->id, temp);
> - thermal_debug_update_temp(tz);
> }
>
> static void thermal_zone_device_check(struct work_struct *work)
> @@ -505,6 +504,8 @@ void __thermal_zone_device_update(struct
> if (governor->manage)
> governor->manage(tz);
>
> + thermal_debug_update_temp(tz);
> +
> monitor_thermal_zone(tz);
> }
>
> Index: linux-pm/drivers/thermal/thermal_debugfs.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_debugfs.c
> +++ linux-pm/drivers/thermal/thermal_debugfs.c
> @@ -545,7 +545,6 @@ void thermal_debug_tz_trip_up(struct the
> struct tz_episode *tze;
> struct tz_debugfs *tz_dbg;
> struct thermal_debugfs *thermal_dbg = tz->debugfs;
> - int temperature = tz->temperature;
> int trip_id = thermal_zone_trip_id(tz, trip);
> ktime_t now = ktime_get();
>
> @@ -614,12 +613,6 @@ void thermal_debug_tz_trip_up(struct the
>
> tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
> tze->trip_stats[trip_id].timestamp = now;
> - tze->trip_stats[trip_id].max = max(tze->trip_stats[trip_id].max, temperature);
> - tze->trip_stats[trip_id].min = min(tze->trip_stats[trip_id].min, temperature);
> - tze->trip_stats[trip_id].count++;
> - tze->trip_stats[trip_id].avg = tze->trip_stats[trip_id].avg +
> - (temperature - tze->trip_stats[trip_id].avg) /
> - tze->trip_stats[trip_id].count;
>
> unlock:
> mutex_unlock(&thermal_dbg->lock);
>
>
>
>

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>