linux-kernel - Re: [PATCH] cpufreq: stats: Do not populate stats when policy->cur has no exact match

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Date:	Mon, 18 Nov 2013 09:34:11 -0600
From:	Nishanth Menon <nm@...com>
To:	Viresh Kumar <viresh.kumar@...aro.org>
CC:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Carlos Hernandez <ceh@...com>,
	Tobias Diedrich <ranma+xen@...edrich.de>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Dave Jones <davej@...hat.com>
Subject: Re: [PATCH] cpufreq: stats: Do not populate stats when policy->cur
 has no exact match

On 11/18/2013 09:22 AM, Viresh Kumar wrote:
> On 18 November 2013 20:38, Nishanth Menon <nm@...com> wrote:
>> On 11/15/2013 11:22 PM, viresh kumar wrote:
> 
>>> I have a untested patch for this. If this looks okay, Nishant can you please try
>>> below patch? With some fixups from your side :)
>>
>> http://pastebin.mozilla.org/3628975
>>
>> I agree that it does show something
> 
> Were you required to update it or fix it? Or you used it as is?

as is - though manually applied ;)

> 
>> but would we not rather prefer to
>> stick with the entries available in freq_table than have to deal with
>> invalid frequencies that may be provided by the driver? for example:
>> how do we in stat know that there will only be one invalid frequency
>> request?
> 
> We don't have to. Actually there is nothing like an invalid freq, as system
> is able to run with it. Its only if kernel is allowed to switch to that
> frequency or not.

depends on how we look at it.. if we consider freq_table as a list of
valid frequencies, anything that is not in there is an invalid entry.
why should stat support it when freq_table is enforced by cpufreq layer?

> 
> This information will be useful for platform developers to know that kernel
> was running on some out of freq-table freq for some time, what that
> frequency was their job to find out and kernel doesn't need to print all
> out of range frequencies. Keeping a single entry for that is more than
> sufficient..
yeah, I guessed that.. no strong feelings other wise..

> 
> Though I personally didn't like: 4294967295 to be printed there.. Will
> see if I can improve that, but its obviously looks better than failing
> in cpufreq-stats..

> 
>> there are some patch wrapping that thunderbird tends to do - I prefer
>> mutt that way, when I need to send inline patches :).
> 
> There are steps in Documentation/email-clients.txt to get that fixed.. I
> have used thunderbird for several years and never found anything
> wrong with sending inline patches..

:) -> https://patchwork.kernel.org/patch/3192211/ shows how confused
my git am  feels ;)


-- 
Regards,
Nishanth Menon
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