From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755543AbYJFVVq (ORCPT ); Mon, 6 Oct 2008 17:21:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752915AbYJFVVi (ORCPT ); Mon, 6 Oct 2008 17:21:38 -0400 Received: from casper.infradead.org ([85.118.1.10]:38408 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752802AbYJFVVi (ORCPT ); Mon, 6 Oct 2008 17:21:38 -0400 Date: Mon, 6 Oct 2008 14:21:31 -0700 From: Arjan van de Ven To: Andi Kleen Cc: Andi Kleen , linux-kernel@vger.kernel.org, Steven Rostedt , mingo@elte.hu, Peter Zijlstra , lenb@kernel.org Subject: Re: PATCH] ftrace: Add a C/P state tracer to help power optimization Message-ID: <20081006142131.37104893@infradead.org> In-Reply-To: <20081006211939.GL3180@one.firstfloor.org> References: <20081006102640.481acd23@infradead.org> <87y711moz2.fsf@basil.nowhere.org> <20081006135715.6a52e954@infradead.org> <20081006211939.GL3180@one.firstfloor.org> Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.12; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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