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SubjectRe: [PATCH 2/7] Cpuidle: Use actual state latency in menu governor
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 */
>


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