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| author | Tero Kristo <tero.kristo@nokia.com> | 2011-02-24 17:19:23 +0200 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2011-05-29 00:35:47 -0400 |
| commit | 7467571f4480b273007517b26297c07154c73924 (patch) | |
| tree | e933b8cff072f5ec389cd5e20c85e756e49cafeb | |
| parent | 521cb40b0c44418a4fd36dc633f575813d59a43d (diff) | |
| download | linux-3.10-7467571f4480b273007517b26297c07154c73924.tar.gz linux-3.10-7467571f4480b273007517b26297c07154c73924.tar.bz2 linux-3.10-7467571f4480b273007517b26297c07154c73924.zip | |
cpuidle: menu: fixed wrapping timers at 4.294 seconds
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.
cc: stable@kernel.org # .32.x through .39.x
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | 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 f508690eb95..c47f3d09c1e 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); |