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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
 "Rafael J. Wysocki" <rafael@kernel.org>, Lukasz Luba <lukasz.luba@arm.com>,
 Daniel Lezcano <daniel.lezcano@linaro.org>
Subject:
 [PATCH v1 3/3] thermal/debugfs: Avoid printing zero duration for mitigation
 episodes in progress
Date: Tue, 23 Apr 2024 20:02:16 +0200
Message-ID: <2933330.e9J7NaK4W3@kreacher>
In-Reply-To: <5774279.DvuYhMxLoT@kreacher>
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=46rom: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If a thermal mitigation event is in progress, its duration value has
not been updated yet, so 0 will be printed as the event duration by
tze_seq_show() which is confusing.

Avoid doing that by marking the beginning of the event with the
KTIME_MIN duration value and making tze_seq_show() compute the current
event duration on the fly, in which case '>' will be printed instead of
'=3D' in the event duration value field.

Similarly, for trip points that have been crossed on the down, mark
the end of mitigation with the KTIME_MAX timestamp value and make
tze_seq_show() compute the current duration on the fly for the trip
points still involved in the mitigation, in which cases the duration
value printed by it will be prepended with a '>' character.

=46ixes: 7ef01f228c9f ("thermal/debugfs: Add thermal debugfs information fo=
r mitigation episodes")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
=2D--
 drivers/thermal/thermal_debugfs.c |   39 ++++++++++++++++++++++++++++++++-=
=2D----
 1 file changed, 33 insertions(+), 6 deletions(-)

Index: linux-pm/drivers/thermal/thermal_debugfs.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=2D-- linux-pm.orig/drivers/thermal/thermal_debugfs.c
+++ linux-pm/drivers/thermal/thermal_debugfs.c
@@ -530,6 +530,7 @@ static struct tz_episode *thermal_debugf
=20
 	INIT_LIST_HEAD(&tze->node);
 	tze->timestamp =3D now;
+	tze->duration =3D KTIME_MIN;
=20
 	for (i =3D 0; i < tz->num_trips; i++) {
 		tze->trip_stats[i].min =3D INT_MAX;
@@ -665,6 +666,9 @@ void thermal_debug_tz_trip_down(struct t
 	tze->trip_stats[trip_id].duration =3D
 		ktime_add(delta, tze->trip_stats[trip_id].duration);
=20
+	/* Mark the end of mitigation for this trip point. */
+	tze->trip_stats[trip_id].timestamp =3D KTIME_MAX;
+
 	/*
 	 * This event closes the mitigation as we are crossing the
 	 * last trip point the way down.
@@ -742,15 +746,25 @@ static int tze_seq_show(struct seq_file
 	struct thermal_trip_desc *td;
 	struct tz_episode *tze;
 	const char *type;
+	u64 duration_ms;
 	int trip_id;
+	char c;
=20
 	tze =3D list_entry((struct list_head *)v, struct tz_episode, node);
=20
=2D	seq_printf(s, ",-Mitigation at %lluus, duration=3D%llums\n",
=2D		   ktime_to_us(tze->timestamp),
=2D		   ktime_to_ms(tze->duration));
+	if (tze->duration =3D=3D KTIME_MIN) {
+		/* Mitigation in progress. */
+		duration_ms =3D ktime_to_ms(ktime_sub(ktime_get(), tze->timestamp));
+		c =3D '>';
+	} else {
+		duration_ms =3D ktime_to_ms(tze->duration);
+		c =3D '=3D';
+	}
+
+	seq_printf(s, ",-Mitigation at %lluus, duration%c%llums\n",
+		   ktime_to_us(tze->timestamp), c, duration_ms);
=20
=2D	seq_printf(s, "| trip |     type | temp(=C2=B0mC) | hyst(=C2=B0mC) |  d=
uration  |  avg(=C2=B0mC) |  min(=C2=B0mC) |  max(=C2=B0mC) |\n");
+	seq_printf(s, "| trip |     type | temp(=C2=B0mC) | hyst(=C2=B0mC) |  dur=
ation   |  avg(=C2=B0mC) |  min(=C2=B0mC) |  max(=C2=B0mC) |\n");
=20
 	for_each_trip_desc(tz, td) {
 		const struct thermal_trip *trip =3D &td->trip;
@@ -782,12 +796,25 @@ static int tze_seq_show(struct seq_file
 		else
 			type =3D "hot";
=20
=2D		seq_printf(s, "| %*d | %*s | %*d | %*d | %*lld | %*d | %*d | %*d |\n",
+		if (trip_stats->timestamp !=3D KTIME_MAX) {
+			/* Mitigation in progress. */
+			ktime_t delta =3D ktime_sub(ktime_get(),
+						  trip_stats->timestamp);
+
+			delta =3D ktime_add(delta, trip_stats->duration);
+			duration_ms =3D ktime_to_ms(delta);
+			c =3D '>';
+		} else {
+			duration_ms =3D ktime_to_ms(trip_stats->duration);
+			c =3D ' ';
+		}
+
+		seq_printf(s, "| %*d | %*s | %*d | %*d | %c%*lld | %*d | %*d | %*d |\n",
 			   4 , trip_id,
 			   8, type,
 			   9, trip->temperature,
 			   9, trip->hysteresis,
=2D			   10, ktime_to_ms(trip_stats->duration),
+			   c, 10, duration_ms,
 			   9, trip_stats->avg,
 			   9, trip_stats->min,
 			   9, trip_stats->max);