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

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Date:	Tue, 22 Apr 2014 08:27:53 +0530
From:	Chander Kashyap <chander.kashyap@...aro.org>
To:	Tuukka Tikkanen <tuukka.tikkanen@...aro.org>
Cc:	"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

ping

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>



-- 
with warm regards,
Chander Kashyap
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