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Subject[PATCH 2/7] Cpuidle: Use actual state latency in menu governor
Date
Currently menu governor records the exit latency of the state it has
chosen for the idle period. The stored latency value is then later
used to calculate the actual length of the idle period. This value
may however be incorrect, as the entered state may not be the one
chosen by the governor. The entered state information is available,
so we can use that to obtain the real exit latency.

Signed-off-by: Tuukka Tikkanen <tuukka.tikkanen@linaro.org>
---
drivers/cpuidle/governors/menu.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index e9a2a27..115386a 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -124,7 +124,6 @@ struct menu_device {

unsigned int next_timer_us;
unsigned int predicted_us;
- unsigned int exit_us;
unsigned int bucket;
unsigned int correction_factor[BUCKETS];
unsigned int intervals[INTERVALS];
@@ -298,7 +297,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
}

data->last_state_idx = 0;
- data->exit_us = 0;

/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0))
@@ -359,7 +357,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
continue;

data->last_state_idx = i;
- data->exit_us = s->exit_latency;
}

return data->last_state_idx;
@@ -410,8 +407,8 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* We correct for the exit latency; we are assuming here that the
* exit latency happens after the event that we're interested in.
*/
- if (measured_us > data->exit_us)
- measured_us -= data->exit_us;
+ if (measured_us > target->exit_latency)
+ measured_us -= target->exit_latency;


/* Update our correction ratio */
--
1.7.9.5


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