linux-kernel - Re: [PATCH] cpufreq: Avoid calling cpufreq driver's target() routine if target

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Date:	Fri, 26 Oct 2012 13:17:12 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	cpufreq@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linaro-dev@...ts.linaro.org, patches@...aro.org,
	pdsw-power-team@....com
Subject: Re: [PATCH] cpufreq: Avoid calling cpufreq driver's target() routine if target_freq == policy->cur

On Friday, October 26, 2012 03:06:26 PM Viresh Kumar wrote:
> Avoid calling cpufreq driver's target() routine if new frequency is same as
> policies current frequency.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

Looks reasonable.

Any objection from anyone?

Rafael


> ---
>  drivers/cpufreq/cpufreq.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 261ef65..28dc134 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1476,6 +1476,10 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
>  
>  	pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
>  		target_freq, relation);
> +
> +	if (target_freq == policy->cur)
> +		return 0;
> +
>  	if (cpu_online(policy->cpu) && cpufreq_driver->target)
>  		retval = cpufreq_driver->target(policy, target_freq, relation);
>  
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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