From: Arjan van de Ven <arjan@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
mingo@elte.hu, Peter Zijlstra <a.p.zijlstra@chello.nl>,
lenb@kernel.org
Subject: Re: PATCH] ftrace: Add a C/P state tracer to help power optimization
Date: Mon, 6 Oct 2008 14:21:31 -0700 [thread overview]
Message-ID: <20081006142131.37104893@infradead.org> (raw)
In-Reply-To: <20081006211939.GL3180@one.firstfloor.org>
> > the link between P states and frequency is... rather lose.
> > Especially with Turbo Mode it no longer is really relevant to list
> > frequencies.
>
> It would probably be less confusing for everyone if the higher level
> cpufreq layers reported the correct frequency for turbo mode too.
> I haven't checked how complicated this would be.
it's impossible until after the fact; you don't know which frequencies
you got until you check back later.
> Ok.
>
> That means that when a CPU is idle forever there won't be any output?
correct; it'll wait until it stops being idle before telling you how
long it was idle.
if it really bothers you we could do a dummy broadcast ipi on shutting
down the tracer.. in practice it's not a problem.
(we wake up all cpus all the time)
--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
next prev parent reply other threads:[~2008-10-06 21:21 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-06 17:26 PATCH] ftrace: Add a C/P state tracer to help power optimization Arjan van de Ven
2008-10-06 20:46 ` Andi Kleen
2008-10-06 20:57 ` Arjan van de Ven
2008-10-06 21:19 ` Andi Kleen
2008-10-06 21:21 ` Arjan van de Ven [this message]
2008-10-06 21:34 ` Andi Kleen
2008-10-07 10:39 ` Steven Rostedt
2008-10-27 15:59 ` Ingo Molnar
2008-10-27 16:05 ` Steven Rostedt
2008-10-27 16:21 ` Alan Cox
2008-10-27 17:16 ` Steven Rostedt
2008-10-27 18:05 ` Arjan van de Ven
2008-10-27 19:47 ` Frank Ch. Eigler
2008-10-27 20:13 ` Steven Rostedt
2008-10-27 21:06 ` Arjan van de Ven
2008-10-28 10:04 ` Ingo Molnar
2009-02-10 20:57 ` Jason Baron
2009-02-10 21:26 ` Frederic Weisbecker
2009-02-11 9:30 ` Ingo Molnar
2009-02-11 18:57 ` Jason Baron
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