applied to idle-test
thanks,
Len Brown, Intel Open Source Technology Center
ps. please cc linux-pm on cpuidle pathces
On Thu, 24 Feb 2011, Tero Kristo wrote:
> Cpuidle menu governor is using u32 as a temporary datatype for storing
> nanosecond values which wrap around at 4.294 seconds. This causes errors
> in predicted sleep times resulting in higher than should be C state
> selection and increased power consumption. This also breaks cpuidle
> state residency statistics.
>
> Signed-off-by: Tero Kristo <tero.kristo@xxxxxxxxx>
> ---
> drivers/cpuidle/governors/menu.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
> index f508690..c47f3d0 100644
> --- a/drivers/cpuidle/governors/menu.c
> +++ b/drivers/cpuidle/governors/menu.c
> @@ -237,6 +237,7 @@ static int menu_select(struct cpuidle_device *dev)
> unsigned int power_usage = -1;
> int i;
> int multiplier;
> + struct timespec t;
>
> if (data->needs_update) {
> menu_update(dev);
> @@ -251,8 +252,9 @@ static int menu_select(struct cpuidle_device *dev)
> return 0;
>
> /* determine the expected residency time, round up */
> + t = ktime_to_timespec(tick_nohz_get_sleep_length());
> data->expected_us =
> - DIV_ROUND_UP((u32)ktime_to_ns(tick_nohz_get_sleep_length()), 1000);
> + t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC;
>
>
> data->bucket = which_bucket(data->expected_us);
> --
> 1.7.1
>
> --
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