[PATCH 2/7] thermal: stats: track number of change requests due to tz

Eduardo Valentin
2023-05-19T03:28:01Z

From: Eduardo Valentin <eduval@amazon.com>

This patch improves the current cooling device
statistics by adding a new file under
cdev/stats/requests_of_thermal_zone

to represent the number of times each thermal zone
requested the cooling device to effectively change.
If the request associated was not serviced because
another thermal zone asked for a higher cooling level,
this counter does not increase.

The file format is:
thermal_zone: <type> <count>

Samples:
$ cat cdev0/stats/requests_of_thermal_zone
thermal_zone: amb0 2

In this example, it means the thermal zone 'amb0' has requested
2 times for cdev0 to change state.

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_core.h | 1 +
drivers/thermal/thermal_sysfs.c | 52 +++++++++++++++++++
3 files changed, 55 insertions(+)

diff --git a/Documentation/driver-api/thermal/sysfs-api.rst b/Documentation/driver-api/thermal/sysfs-api.rst
index caa50d61a5bc..75309a51d9b3 100644
--- a/Documentation/driver-api/thermal/sysfs-api.rst
+++ b/Documentation/driver-api/thermal/sysfs-api.rst
@@ -369,6 +369,8 @@ Thermal cooling device sys I/F, created once it's registered::
|---stats/trans_table: Cooling state transition table
|---stats/time_in_thermal_zone_ms: Time that this cooling device was driven
each associated thermal zone.
+ |---stats/requests_of_thermal_zone: Total number of times this cooling device
+ changed due to each associated thermal zone.

Then next two dynamic attributes are created/removed in pairs. They represent
diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
index 3cce60c6e065..ed6511c3b794 100644
--- a/drivers/thermal/thermal_core.h
+++ b/drivers/thermal/thermal_core.h
@@ -103,6 +103,7 @@ struct thermal_instance {
unsigned int weight; /* The weight of the cooling device */
bool upper_no_limit;
#if IS_ENABLED(CONFIG_THERMAL_STATISTICS)
+ unsigned long total_requests;
ktime_t time_in; /* time spent in this instance */
#endif
};
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index a3b71f03db75..0bce1415f7e8 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -723,6 +723,7 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
stats->trans_table[stats->state * (cdev->max_state + 1) + new_state]++;
stats->state = new_state;
stats->total_trans++;
+ stats->curr_instance->total_requests++;

unlock:
spin_unlock(&stats->lock);
@@ -867,6 +868,54 @@ time_in_thermal_zone_ms_show(struct device *dev, struct device_attribute *attr,
return ret < 0 ? ret : len;
}

+static ssize_t
+requests_of_thermal_zone_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ LIST_HEAD(cdev_thermal_zone_list);
+ struct thermal_cooling_device *cdev = to_cooling_device(dev);
+ struct cooling_dev_stats *stats = cdev->stats;
+ struct cdev_thermal_zone_residency *res, *next;
+ struct thermal_instance *instance;
+ ssize_t len = 0, ret = 0;
+
+ mutex_lock(&cdev->lock);
+
+ spin_lock(&stats->lock);
+ update_time_in_state(stats, stats->curr_instance);
+ spin_unlock(&stats->lock);
+
+ build_cdev_thermal_zone_residency(&cdev_thermal_zone_list, cdev);
+
+ list_for_each_entry(instance, &cdev->thermal_instances, cdev_node)
+ list_for_each_entry(res, &cdev_thermal_zone_list, node)
+ if (strncmp(res->thermal_zone, instance->tz->type,
+ THERMAL_NAME_LENGTH) == 0)
+ res->counter += instance->total_requests;
+
+ mutex_unlock(&cdev->lock);
+
+ list_for_each_entry_safe(res, next, &cdev_thermal_zone_list, node) {
+ ret = sprintf(buf + len, "thermal_zone: %s\t%lu\n",
+ res->thermal_zone, res->counter);
+
+ if (ret == 0)
+ ret = -EOVERFLOW;
+
+ if (ret < 0)
+ break;
+
+ len += ret;
+ }
+
+ list_for_each_entry_safe(res, next, &cdev_thermal_zone_list, node) {
+ list_del(&res->node);
+ kfree(res);
+ }
+
+ return ret < 0 ? ret : len;
+}
+
static ssize_t
reset_store(struct device *dev, struct device_attribute *attr, const char *buf,
size_t count)
@@ -897,6 +946,7 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf,

/* Make sure we reset all counters per instance */
list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
+ instance->total_requests = 0;
instance->time_in = ktime_set(0, 0);
}

@@ -971,6 +1021,7 @@ static ssize_t trans_table_show(struct device *dev,
static DEVICE_ATTR_RO(total_trans);
static DEVICE_ATTR_RO(time_in_state_ms);
static DEVICE_ATTR_RO(time_in_thermal_zone_ms);
+static DEVICE_ATTR_RO(requests_of_thermal_zone);
static DEVICE_ATTR_WO(reset);
static DEVICE_ATTR_RO(trans_table);

@@ -978,6 +1029,7 @@ static struct attribute *cooling_device_stats_attrs[] = {
&dev_attr_total_trans.attr,
&dev_attr_time_in_state_ms.attr,
&dev_attr_time_in_thermal_zone_ms.attr,
+ &dev_attr_requests_of_thermal_zone.attr,
&dev_attr_reset.attr,
&dev_attr_trans_table.attr,
NULL
--
2.34.1