linux-kernel - Re: [PATCH v7 2/4] cpufreq: ondemand: call dbs_check

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Date:	Thu, 31 Jan 2013 10:06:11 +0100
From:	Fabio Baltieri <fabio.baltieri@...aro.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org, Linus Walleij <linus.walleij@...aro.org>,
	swarren@...dotorg.org, linaro-dev@...ts.linaro.org,
	Nicolas Pitre <nicolas.pitre@...aro.org>,
	mathieu.poirier@...aro.org, Joseph Lo <josephl@...dia.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 2/4] cpufreq: ondemand: call dbs_check_cpu only when
 necessary

On Thu, Jan 31, 2013 at 02:12:29PM +0530, Viresh Kumar wrote:
> On 31 January 2013 14:09, Fabio Baltieri <fabio.baltieri@...aro.org> wrote:
> > Ok, now I see the problem: cdbs->cpu is initialized only on the leader
> > cpu and this is working by coincidence on my system, while
> > cdbs->time_stamp is initialized only on the leader cpu, and that should
> > be correct even when cpu hotplugging as that's reinitialized every time.
> >
> > That's a fix so I'll send a patch just to set ->cpu into the
> > for_each_cpu cycle.
> 
> That's not enough. You need to set ->cpu to j and not policy->cpu as we
> discussed it earlier (params to timer init and exit.).
> 
> And so, we need to get policy->cpu somehow and get its timestamp.

Current code uses ->cpu to track policy->cpu and get the timestamp, I
can modify it to point to the current cpu and use it in timer_init *and*
add a new field just to track leader_cpu but I don't see the benefits.
Am I missing something?

Fabio

-- 
Fabio Baltieri
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