a1383655cf
Tested on bcm2710 (Raspberry Pi 3B). Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
95 lines
3.3 KiB
Diff
95 lines
3.3 KiB
Diff
From c14122415c0b53cd234d058a55e7183a750a0eda Mon Sep 17 00:00:00 2001
|
|
From: Ram Chandrasekar <rkumbako@codeaurora.org>
|
|
Date: Mon, 7 May 2018 11:54:08 -0600
|
|
Subject: [PATCH] drivers: thermal: step_wise: add support for
|
|
hysteresis
|
|
|
|
Step wise governor increases the mitigation level when the temperature
|
|
goes above a threshold and will decrease the mitigation when the
|
|
temperature falls below the threshold. If it were a case, where the
|
|
temperature hovers around a threshold, the mitigation will be applied
|
|
and removed at every iteration. This reaction to the temperature is
|
|
inefficient for performance.
|
|
|
|
The use of hysteresis temperature could avoid this ping-pong of
|
|
mitigation by relaxing the mitigation to happen only when the
|
|
temperature goes below this lower hysteresis value.
|
|
|
|
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>
|
|
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
|
|
---
|
|
drivers/thermal/step_wise.c | 33 +++++++++++++++++++++++----------
|
|
1 file changed, 23 insertions(+), 10 deletions(-)
|
|
|
|
--- a/drivers/thermal/step_wise.c
|
|
+++ b/drivers/thermal/step_wise.c
|
|
@@ -24,7 +24,7 @@
|
|
* for this trip point
|
|
* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
|
|
* for this trip point
|
|
- * If the temperature is lower than a trip point,
|
|
+ * If the temperature is lower than a hysteresis temperature,
|
|
* a. if the trend is THERMAL_TREND_RAISING, do nothing
|
|
* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
|
|
* state for this trip point, if the cooling state already
|
|
@@ -115,7 +115,7 @@ static void update_passive_instance(stru
|
|
|
|
static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
|
|
{
|
|
- int trip_temp;
|
|
+ int trip_temp, hyst_temp;
|
|
enum thermal_trip_type trip_type;
|
|
enum thermal_trend trend;
|
|
struct thermal_instance *instance;
|
|
@@ -123,22 +123,23 @@ static void thermal_zone_trip_update(str
|
|
int old_target;
|
|
|
|
if (trip == THERMAL_TRIPS_NONE) {
|
|
- trip_temp = tz->forced_passive;
|
|
+ hyst_temp = trip_temp = tz->forced_passive;
|
|
trip_type = THERMAL_TRIPS_NONE;
|
|
} else {
|
|
tz->ops->get_trip_temp(tz, trip, &trip_temp);
|
|
+ hyst_temp = trip_temp;
|
|
+ if (tz->ops->get_trip_hyst) {
|
|
+ tz->ops->get_trip_hyst(tz, trip, &hyst_temp);
|
|
+ hyst_temp = trip_temp - hyst_temp;
|
|
+ }
|
|
tz->ops->get_trip_type(tz, trip, &trip_type);
|
|
}
|
|
|
|
trend = get_tz_trend(tz, trip);
|
|
|
|
- if (tz->temperature >= trip_temp) {
|
|
- throttle = true;
|
|
- trace_thermal_zone_trip(tz, trip, trip_type);
|
|
- }
|
|
-
|
|
- dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d]:trend=%d,throttle=%d\n",
|
|
- trip, trip_type, trip_temp, trend, throttle);
|
|
+ dev_dbg(&tz->device,
|
|
+ "Trip%d[type=%d,temp=%d,hyst=%d]:trend=%d,throttle=%d\n",
|
|
+ trip, trip_type, trip_temp, hyst_temp, trend, throttle);
|
|
|
|
mutex_lock(&tz->lock);
|
|
|
|
@@ -147,6 +148,18 @@ static void thermal_zone_trip_update(str
|
|
continue;
|
|
|
|
old_target = instance->target;
|
|
+ throttle = false;
|
|
+ /*
|
|
+ * Lower the mitigation only if the temperature
|
|
+ * goes below the hysteresis temperature.
|
|
+ */
|
|
+ if (tz->temperature >= trip_temp ||
|
|
+ (tz->temperature >= hyst_temp &&
|
|
+ old_target != THERMAL_NO_TARGET)) {
|
|
+ throttle = true;
|
|
+ trace_thermal_zone_trip(tz, trip, trip_type);
|
|
+ }
|
|
+
|
|
instance->target = get_target_state(instance, trend, throttle);
|
|
dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
|
|
old_target, (int)instance->target);
|