[2/7] Cpuidle: Use actual state latency in menu governor

Message ID 1393223377-5744-3-git-send-email-tuukka.tikkanen@linaro.org
State Accepted
Commit 22695ab6314083d9d045ce9276e9ae79eb889531
Headers show

Commit Message

Tuukka Tikkanen Feb. 24, 2014, 6:29 a.m.
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(-)

Comments

Daniel Lezcano Feb. 24, 2014, 10:35 p.m. | #1
On 02/24/2014 07:29 AM, Tuukka Tikkanen wrote:
> 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>

Acked-by: Daniel Lezcano <daniel.lezcano@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 */
>

Patch

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 */