Messages in this thread | | | Date | Fri, 01 Apr 2011 20:07:04 -0400 (EDT) | From | Len Brown <> | Subject | Re: [PATCH] cpuidle: menu: fixed wrapping timers at 4.294 seconds |
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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@nokia.com> > --- > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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