linux-kernel - Re: [PATCH v2] cpufreq: stats: Add 'load_table' debugfs file to show accumulated data of CPUs

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Date:	Fri, 21 Jun 2013 15:13:39 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Chanwoo Choi <cw00.choi@...sung.com>
Cc:	Viresh Kumar <viresh.kumar@...aro.org>,
	linux-kernel@...r.kernel.org,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Myungjoo Ham <myungjoo.ham@...sung.com>
Subject: Re: [PATCH v2] cpufreq: stats: Add 'load_table' debugfs file to show accumulated data of CPUs

On Friday, June 21, 2013 01:01:35 PM Chanwoo Choi wrote:
> On 06/21/2013 12:42 AM, Viresh Kumar wrote:
> > On 20 June 2013 16:48, Chanwoo Choi <cw00.choi@...sung.com> wrote:
> >> But,
> >> To show old frequency/new frequency on load_table debugfs file,
> >> governor function(dbs_check_cpu()) pass calculated CPUs load to specific governor(e.g., ondemand)
> >> as below function flow.
> >>
> >> dbs_check_cpu() (in cpufreq.c)
> >> -> od_check_cpu() (in cpufreq_ondemand.c)
> >> -> __cpufreq_driver_target() (in cpufreq.c)
> >> -> cpufreq_driver->target(policy)
> >>
> >> Also, The __cpufreq_driver_target() is external function which can be called on other file
> >> so I must consider exception case.
> >>
> >> If send CPUFREQ_LOADCHECK noti after changed cpu frequency,
> >> I think it is complicated and has quite a little difficulty.
> >>
> >> What is your opinion?
> > 
> > What you can do is:
> > - create another routine: cpufreq_governor_driver_target()
> > - replace all __cpufreq_driver_target() from ondemand/conservative governors
> > with this one
> > - In cpufreq_governor_driver_target() call __cpufreq_driver_target() and
> > take a note of new freq.
> > 
> > Maybe you don't need to check the actual freq that is set (even
> > that would be simple to implement), but what is requested.
> > 
> 
> OK, I understand and will try to implement it.
> Thanks.
> 
> @Rafael?
> If possible, I want to know the your opinion about this.

Well, to be honest, I don't like the whole thing.  The more changes you need
to make to the common code to support it, the worse.

Thanks,
Rafael


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