linux-kernel - Re: [PATCH RESEND] cpufreq: Break out early when frequency equals target

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Message-ID: <CAKohpoktAkaA=do3or6VYzVEjyZcSe+eexqxvTj1HPrx-3+vfw@mail.gmail.com>
Date:	Thu, 15 May 2014 10:09:47 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Stratos Karafotis <stratosk@...aphore.gr>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND] cpufreq: Break out early when frequency equals target_freq

On 14 May 2014 23:35, Stratos Karafotis <stratosk@...aphore.gr> wrote:
> Many drivers keep frequencies in frequency table in ascending
> or descending order. When governor tries to change to policy->min
> or policy->max respectively then the cpufreq_frequency_table_target
> could return on first iteration. This will save some iteration cycles.
>
> So, break out early when a frequency in cpufreq_frequency_table
> equals to target one.
>
> Testing this during kernel compilation using ondemand governor
> with a frequency table in ascending order, the
> cpufreq_frequency_table_target returned early on the first
> iteration at about 30% of times called.
>
> Signed-off-by: Stratos Karafotis <stratosk@...aphore.gr>
> ---
>  drivers/cpufreq/freq_table.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
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