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authorJavi Merino <javi.merino@arm.com>2015-02-18 16:04:25 +0000
committerEduardo Valentin <edubezval@gmail.com>2015-05-04 21:27:51 -0700
commitbcdcbbc71125c37195f97314f453ca9a3a4eb758 (patch)
tree886c2d24fab01346384d956f8f4c874a626ab3c7 /drivers/thermal/fair_share.c
parentdb91651311c8b89978b17d27634582c28c33363e (diff)
thermal: fair_share: generalize the weight concept
The fair share governor has the concept of weights, which is the influence of each cooling device in a thermal zone. The current implementation forces the weights of all cooling devices in a thermal zone to add up to a 100. This complicates setups, as you need to know in advance how many cooling devices you are going to have. If you bind a new cooling device, you have to modify all the other cooling devices weights, which is error prone. Furthermore, you can't specify a "default" weight for platforms since that default value depends on the number of cooling devices in the platform. This patch generalizes the concept of weight by allowing any number to be a "weight". Weights are now relative to each other. Platforms that don't specify weights get the same default value for all their cooling devices, so all their cdevs are considered to be equally influential. It's important to note that previous users of the weights don't need to alter the code: percentages continue to work as they used to. This patch just removes the constraint of all the weights in a thermal zone having to add up to a 100. If they do, you get the same behavior as before. If they don't, fair share now works for that platform. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Durgadoss R <durgadoss.r@intel.com> Acked-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Diffstat (limited to 'drivers/thermal/fair_share.c')
-rw-r--r--drivers/thermal/fair_share.c26
1 files changed, 21 insertions, 5 deletions
diff --git a/drivers/thermal/fair_share.c b/drivers/thermal/fair_share.c
index 692f4053f08b..c2c10bbe24d6 100644
--- a/drivers/thermal/fair_share.c
+++ b/drivers/thermal/fair_share.c
@@ -59,13 +59,13 @@ static int get_trip_level(struct thermal_zone_device *tz)
}
static long get_target_state(struct thermal_zone_device *tz,
- struct thermal_cooling_device *cdev, int weight, int level)
+ struct thermal_cooling_device *cdev, int percentage, int level)
{
unsigned long max_state;
cdev->ops->get_max_state(cdev, &max_state);
- return (long)(weight * level * max_state) / (100 * tz->trips);
+ return (long)(percentage * level * max_state) / (100 * tz->trips);
}
/**
@@ -77,7 +77,7 @@ static long get_target_state(struct thermal_zone_device *tz,
*
* Parameters used for Throttling:
* P1. max_state: Maximum throttle state exposed by the cooling device.
- * P2. weight[i]/100:
+ * P2. percentage[i]/100:
* How 'effective' the 'i'th device is, in cooling the given zone.
* P3. cur_trip_level/max_no_of_trips:
* This describes the extent to which the devices should be throttled.
@@ -89,16 +89,32 @@ static long get_target_state(struct thermal_zone_device *tz,
static int fair_share_throttle(struct thermal_zone_device *tz, int trip)
{
struct thermal_instance *instance;
+ int total_weight = 0;
+ int total_instance = 0;
int cur_trip_level = get_trip_level(tz);
list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ if (instance->trip != trip)
+ continue;
+
+ total_weight += instance->weight;
+ total_instance++;
+ }
+
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ int percentage;
struct thermal_cooling_device *cdev = instance->cdev;
if (instance->trip != trip)
continue;
- instance->target = get_target_state(tz, cdev,
- instance->weight, cur_trip_level);
+ if (!total_weight)
+ percentage = 100 / total_instance;
+ else
+ percentage = (instance->weight * 100) / total_weight;
+
+ instance->target = get_target_state(tz, cdev, percentage,
+ cur_trip_level);
instance->cdev->updated = false;
thermal_cdev_update(cdev);