linux-kernel - Re: [PATCH] cpuidle: governor: menu: move repeated correction factor check to init

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Date:	Tue, 22 Apr 2014 12:03:02 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Chander Kashyap <chander.kashyap@...aro.org>
Cc:	Tuukka Tikkanen <tuukka.tikkanen@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	rafael.j.wysocki@...el.com,
	Daniel Lezcano <daniel.lezcano@...aro.org>
Subject: Re: [PATCH] cpuidle: governor: menu: move repeated correction factor check to init

On Tuesday, April 22, 2014 08:27:53 AM Chander Kashyap wrote:
> ping

Please CC cpuidle patches to linux-pm@...r.kernel.org.

Thanks!

> On 10 April 2014 19:57, Tuukka Tikkanen <tuukka.tikkanen@...aro.org> wrote:
> > On 10 April 2014 16:43, Chander Kashyap <chander.kashyap@...aro.org> wrote:
> >> In menu_select function we check for correction factor every time.
> >> If it is zero we are initializing to unity. Hence move it to init function
> >> and initialise by unity, hence avoid repeated comparisons.
> >>
> >> Signed-off-by: Chander Kashyap <chander.kashyap@...aro.org>
> >> ---
> >>  drivers/cpuidle/governors/menu.c |   15 ++++++++-------
> >>  1 file changed, 8 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
> >> index cf7f2f0..048f6d9 100644
> >> --- a/drivers/cpuidle/governors/menu.c
> >> +++ b/drivers/cpuidle/governors/menu.c
> >> @@ -315,13 +315,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
> >>         multiplier = performance_multiplier();
> >>
> >>         /*
> >> -        * if the correction factor is 0 (eg first time init or cpu hotplug
> >> -        * etc), we actually want to start out with a unity factor.
> >> -        */
> >> -       if (data->correction_factor[data->bucket] == 0)
> >> -               data->correction_factor[data->bucket] = RESOLUTION * DECAY;
> >> -
> >> -       /*
> >>          * Force the result of multiplication to be 64 bits even if both
> >>          * operands are 32 bits.
> >>          * Make sure to round up for half microseconds.
> >> @@ -453,9 +446,17 @@ static int menu_enable_device(struct cpuidle_driver *drv,
> >>                                 struct cpuidle_device *dev)
> >>  {
> >>         struct menu_device *data = &per_cpu(menu_devices, dev->cpu);
> >> +       int i;
> >>
> >>         memset(data, 0, sizeof(struct menu_device));
> >>
> >> +       /*
> >> +        * if the correction factor is 0 (eg first time init or cpu hotplug
> >> +        * etc), we actually want to start out with a unity factor.
> >> +        */
> >> +       for(i = 0; i < BUCKETS; i++)
> >> +               data->correction_factor[i] = RESOLUTION * DECAY;
> >> +
> >>         return 0;
> >>  }
> >>
> >> --
> >> 1.7.9.5
> >>
> >
> > Reviewed-by: Tuukka Tikkanen <tuukka.tikkanen@...aro.org>
> 
> 
> 
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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