linux-kernel - Re: [PATCH] x86 cpufreq: Make trace_power

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Message-ID: <20100528184213.76c09515@infradead.org>
Date:	Fri, 28 May 2010 18:42:13 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	Thomas Renninger <trenn@...e.de>
Cc:	davej@...hat.com, linux-kernel@...r.kernel.org,
	robert.schoene@...dresden.de, cpufreq@...r.kernel.org,
	linux-perf-users@...r.kernel.org,
	linux-trace-users@...r.kernel.org, x86@...nel.org,
	akpm@...ux-foundation.org
Subject: Re: [PATCH] x86 cpufreq: Make trace_power_frequency cpufreq driver
 independent

On Tue, 25 May 2010 14:39:59 +0200
Thomas Renninger <trenn@...e.de> wrote:

> and fix the broken case if a core's frequency depends on others.
> 
> trace_power_frequency was only implemented in a rather ungeneric way
> in acpi-cpufreq driver's target() function only.
> -> Move the call to trace_power_frequency to
>    cpufreq.c:cpufreq_notify_transition() where CPUFREQ_POSTCHANGE
>    notifier is triggered.
>    This will support power frequency tracing by all cpufreq drivers
> 
> trace_power_frequency did not trace frequency changes correctly when
> the userspace governor was used or when CPU cores' frequency depend
> on each other.
> -> Moving this into the CPUFREQ_POSTCHANGE notifier and pass the cpu
>    which gets switched automatically fixes this.


while I'm no great fan of having a second field in the perf structure
for the cpu... I can see that Thomas has a use case where this solves
his issue...

Acked-by: Arjan van de Ven <arjan@...ux.intel.com>

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
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