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

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Message-ID: <5375DE80.4030707@intel.com>
Date:	Fri, 16 May 2014 11:46:40 +0200
From:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
To:	Chander Kashyap <chander.kashyap@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
CC:	Tuukka Tikkanen <tuukka.tikkanen@...aro.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND][PATCH] cpuidle: governor: menu: move repeated correction
 factor check to init

On 5/16/2014 10:16 AM, Chander Kashyap wrote:
> On 22 April 2014 18:08, 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>
>> Reviewed-by: Tuukka Tikkanen <tuukka.tikkanen@...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 71b5232..9b7918c 100644
>> --- a/drivers/cpuidle/governors/menu.c
>> +++ b/drivers/cpuidle/governors/menu.c
>> @@ -311,13 +311,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
>>          data->bucket = which_bucket(data->next_timer_us);
>>
>>          /*
>> -        * 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.
>> @@ -466,9 +459,17 @@ 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;
>>   }
>>
> ping.

I believe this is in linux-next today, care to check?

Rafael

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