linux-kernel - Re: [Update][PATCH v7 7/7] cpufreq: schedutil: New governor based on scheduler utilization data

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Message-ID: <56FECA9B.20902@linaro.org>
Date:	Fri, 1 Apr 2016 12:23:07 -0700
From:	Steve Muckle <steve.muckle@...aro.org>
To:	"Rafael J. Wysocki" <rafael@...nel.org>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Juri Lelli <juri.lelli@....com>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Michael Turquette <mturquette@...libre.com>,
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [Update][PATCH v7 7/7] cpufreq: schedutil: New governor based on
 scheduler utilization data

On 04/01/2016 12:14 PM, Rafael J. Wysocki wrote:
> On Fri, Apr 1, 2016 at 7:49 PM, Steve Muckle <steve.muckle@...aro.org> wrote:
>> On 03/29/2016 07:00 PM, Rafael J. Wysocki wrote:
>> ...
>>> +config CPU_FREQ_GOV_SCHEDUTIL
>>> +     tristate "'schedutil' cpufreq policy governor"
>>> +     depends on CPU_FREQ
>>> +     select CPU_FREQ_GOV_ATTR_SET
>>> +     select IRQ_WORK
>>> +     help
>>> +       This governor makes decisions based on the utilization data provided
>>> +       by the scheduler.  It sets the CPU frequency to be proportional to
>>> +       the utilization/capacity ratio coming from the scheduler.  If the
>>> +       utilization is frequency-invariant, the new frequency is also
>>> +       proportional to the maximum available frequency.  If that is not the
>>> +       case, it is proportional to the current frequency of the CPU with the
>>> +       tipping point at utilization/capacity equal to 80%.
>>
>> This help text implies that the tipping point of 80% applies only to
>> non-frequency invariant configurations, rather than both. Possible to
>> rephrase?
> 
> Sure.
> 
> What about:
> 
> "If that is not the case, it is proportional to the current frequency
> of the CPU.  The frequency tipping point is at utilization/capacity
> equal to 80% in both cases."

LGTM

thanks,
Steve