Messages in this thread | | | Date | Thu, 26 Sep 2013 00:38:50 +0200 | From | Daniel Lezcano <> | Subject | Re: [PATCH 20/21] cpuidle: don't calculate time-diff if entered_state == 0 |
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On 09/22/2013 03:21 AM, Viresh Kumar wrote: > If entered_state == 0, we don't need to set dev->last_residency to 'diff' as we > will be setting it to zero without using its new value.
I don't get it, can you elaborate. We can be a long time in this state (eg. if the prediction is false).
> And so move calculation of diff also inside the "if" statement. > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpuidle/cpuidle.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > index bf80236..cb81689 100644 > --- a/drivers/cpuidle/cpuidle.c > +++ b/drivers/cpuidle/cpuidle.c > @@ -77,23 +77,22 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, > > struct cpuidle_state *target_state = &drv->states[index]; > ktime_t time_start, time_end; > - s64 diff; > > time_start = ktime_get(); > > entered_state = target_state->enter(dev, drv, index); > > - time_end = ktime_get(); > + if (entered_state >= 0) { > + s64 diff; > > - local_irq_enable(); > + time_end = ktime_get(); > + diff = ktime_to_us(ktime_sub(time_end, time_start)); > > - diff = ktime_to_us(ktime_sub(time_end, time_start)); > - if (diff > INT_MAX) > - diff = INT_MAX; > + if (diff > INT_MAX) > + diff = INT_MAX; > > - dev->last_residency = (int) diff; > + dev->last_residency = (int) diff; > > - if (entered_state >= 0) { > /* Update cpuidle counters */ > /* This can be moved to within driver enter routine > * but that results in multiple copies of same code. > @@ -104,6 +103,8 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, > dev->last_residency = 0; > } > > + local_irq_enable(); > + > return entered_state; > } > >
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