linux-kernel - Re: [PATCH linux-next] cpufreq: conservative: Fix sampling_down

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Message-ID: <CAKohpokvqe8860J=XO_GXqxpNtrt9XEuUeqCeR=A4PpSaAsHYg@mail.gmail.com>
Date:	Tue, 5 Mar 2013 15:34:20 +0800
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Stratos Karafotis <stratosk@...aphore.gr>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH linux-next] cpufreq: conservative: Fix sampling_down_factor
 functionality

On 5 March 2013 13:22, Stratos Karafotis <stratosk@...aphore.gr> wrote:
> I had the same thoughts, but I saw the comments in the code:
>
> /*
>  * Every sampling_rate, we check, if current idle time is less than 20%
>  * (default), then we try to increase frequency Every sampling_rate *
>  * sampling_down_factor, we check, if current idle time is more than 80%, then
>  * we try to decrease frequency

I misread it here when i looked at this mail for the first time. :)
I strongly believe that we need a full stop (.) before "Every sampling_rate",
otherwise it looks like we check for down_factor while increasing freq :)

>  *
>
> Also checking the code before the commit 8e677ce83bf41ba9c74e5b6d9ee60b07d4e5ed93 you may see that sampling down factor works in this way.
> So, I decided to keep the original functionality (also down_skip was already there unused).

I got that comment but i belive the code was never according to that comment
and not even now. Check the initial patch for conservative governor:
b9170836d1aa4ded7cc1ac1cb8fbc7867061c98c

Even now we aren't checking this 80% thing, right? And so in your patch we can
actually fix the patch too with the right logic of code.. And
documentation too :)
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