linux-kernel - Re: [PATCH v3 linux-next] cpufreq: ondemand: Calculate gradient of CPU load to early increase frequency

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Message-ID: <31773720.6bVyeZQsYt@vostro.rjw.lan>
Date:	Wed, 03 Apr 2013 00:55:51 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Stratos Karafotis <stratosk@...aphore.gr>
Cc:	Viresh Kumar <viresh.kumar@...aro.org>, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 linux-next] cpufreq: ondemand: Calculate gradient of CPU load to early increase frequency

On Tuesday, April 02, 2013 06:49:14 PM Stratos Karafotis wrote:
> On 04/02/2013 04:50 PM, Rafael J. Wysocki wrote:
> > Do you have any numbers indicating that this actually makes things better?
> > 
> > Rafael
> 
> No, I don't.
> The expected behaviour after this patch is to "force" max frequency few sampling periods earlier.
> The idea was to increase system responsiveness especially on 'small' embedded systems (phones for example).
> 
> Actually, I thought to provide some numbers but I had no idea how to measure this.
> 
> Would it be enough to provide the number of times that the CPU increases frequency 
> because of early_demand versus the total number of increments?

I think it would be better to check if your approach leads to a better behavior
as far as energy savings are concerned.  If it actually is worse, then I don't
see a reason to apply it.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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