linux-kernel - Re: [PATCH 3/6 v4] cpufreq: tolerate inexact values when collecting stats

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Message-ID: <50B3754A.50804@calxeda.com>
Date:	Mon, 26 Nov 2012 07:57:30 -0600
From:	Mark Langsdorf <mark.langsdorf@...xeda.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
CC:	Borislav Petkov <bp@...en8.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	MyungJoo Ham <myungjoo.ham@...il.com>
Subject: Re: [PATCH 3/6 v4] cpufreq: tolerate inexact values when collecting
 stats

On 11/24/2012 04:05 AM, Rafael J. Wysocki wrote:
> On Saturday, November 17, 2012 03:50:48 PM Borislav Petkov wrote:
>> On Tue, Nov 13, 2012 at 02:13:38PM -0500, Mark Langsdorf wrote:
>>> Although cpufreq_driver has a flag field, no part of cpufreq_driver
>>> is directly passed to the cpufreq_stat code. Only cpufreq_policy
>>> is. It's cleaner to do passes of the while loop than to copy the
>>> cpufreq_driver.flag field into cpufreq_policy and then store it again
>>> in cpufreq_stats.
>>
>> That maybe so but this newly added loop which is only Calxeda-relevant
>> is called in cpufreq_stat_notifier_trans, which is the frequency change
>> notifier call, AFAICT.

Drivers only go through the loop if they can't find an exact frequency.
So every driver that isn't Calxeda shouldn't see the issue.

>> So you probably need to find a slick way of detecting calxeda hw
>> somewhere along the init path of cpufreq_stats_init and set a
>> hw-specific flag instead of adding that cost to each driver.
> 
> Mark, I suppose you'd like me to take this series for v3.8, but the above
> comment from Boris has to be addressed for that.

I think I'd rather drop this particular patch and not have cpufreq_stat
support for Highbank. Redesigning it to meet Boris' requirements is
going to take more time than I currently have available.

Would it be acceptable to drop this patch and fix the issues with
patches 4 and 6 to get the series in?

--Mark Langsdorf
Calxeda, Inc.

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