| Message ID | acd1cc837f969a50582d2b25a73c5e247f40f843.1379779777.git.viresh.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
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; > } > >
On 26 September 2013 04:08, Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > 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. Sure.. We have following code in cpuidle_enter_state(): --------- diff = ktime_to_us(ktime_sub(time_end, time_start)); if (diff > INT_MAX) diff = INT_MAX; 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. */ dev->states_usage[entered_state].time += dev->last_residency; dev->states_usage[entered_state].usage++; } else { dev->last_residency = 0; } ------- We are setting last_residency to 0 when (entered_state < 0) and aren't using the value of "diff". So, we can actually skip calculations of time_end, diff and last_residency when (entered_state < 0).. Makes sense? > We can be a long time in this state > (eg. if the prediction is false). Okay.. I didn't get it :)
On 09/26/2013 08:24 AM, Viresh Kumar wrote: > On 26 September 2013 04:08, Daniel Lezcano <daniel.lezcano@linaro.org> wrote: >> 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. > > Sure.. We have following code in cpuidle_enter_state(): > > --------- > diff = ktime_to_us(ktime_sub(time_end, time_start)); > if (diff > INT_MAX) > diff = INT_MAX; > > 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. > */ > dev->states_usage[entered_state].time += dev->last_residency; > dev->states_usage[entered_state].usage++; > } else { > dev->last_residency = 0; > } > ------- > > We are setting last_residency to 0 when (entered_state < 0) and aren't using > the value of "diff". So, we can actually skip calculations of time_end, diff and > last_residency when (entered_state < 0).. Makes sense? Yes I agree, but why are you saying "If entered_state == 0, we don't need to ..." ? >> We can be a long time in this state >> (eg. if the prediction is false). > > Okay.. I didn't get it :) >
On 26 September 2013 13:55, Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > Yes I agree, but why are you saying "If entered_state == 0, we don't need to > ..." ? Ahh.. that's a mistake.. s/==/< :)
On 09/26/2013 10:28 AM, Viresh Kumar wrote: > On 26 September 2013 13:55, Daniel Lezcano <daniel.lezcano@linaro.org> wrote: >> Yes I agree, but why are you saying "If entered_state == 0, we don't need to >> ..." ? > > Ahh.. that's a mistake.. s/==/< :) Ah ok.
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; }
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. 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(-)