From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Renninger Subject: Re: [PATCH 2/3] perf: add OMAP support for the new power events Date: Mon, 10 Jan 2011 15:14:31 +0100 Message-ID: <201101101514.32355.trenn@suse.de> References: <1294136263-24020-1-git-send-email-j-pihet@ti.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from cantor.suse.de ([195.135.220.2]:57103 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751756Ab1AJOOo (ORCPT ); Mon, 10 Jan 2011 09:14:44 -0500 In-Reply-To: Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Jean Pihet Cc: Paul Walmsley , mingo@elte.hu, Kevin Hilman , Tony Lindgren , Russell King , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Arjan van de Ven , linux-perf-users@vger.kernel.org, rjw@sisk.pl, Jean Pihet On Wednesday 05 January 2011 12:05:18 Jean Pihet wrote: > Hi Paul, > > On Tue, Jan 4, 2011 at 7:48 PM, Paul Walmsley wrote: > > Hello Jean, > > > > On Tue, 4 Jan 2011, jean.pihet@newoldbits.com wrote: > > > >> From: Jean Pihet > >> > >> The patch adds the new power management trace points for > >> the OMAP architecture. > >> > >> The trace points are for: > >> - default idle handler. Since the cpuidle framework is > >> instrumented in the generic way there is no need to > >> add trace points in the OMAP specific cpuidle handler; > >> - cpufreq (DVFS), > >> - clocks changes (enable, disable, set_rate), > > > > A question about these. Are these only meant to track calls to these > > functions from outside the clock code? Or meant to track actual hardware > > clock changes? > The former: this is used to track the clock requests from outside the > clock framework. > > > If the latter, then it might make sense to put these > > trace points into the functions that actually change the hardware > > registers, e.g., omap2_dflt_clk_{enable,disable}(), etc., since a > > clk_enable() on a leaf clock may result in many internal system clocks > > being enabled up the clock tree. > I agree with you it is better to track the actual clock changes instead. > I propose to move the tracepoints to omap2_clk_{enable...} which > enables all the clocks irrespectively of the installed handler. > Note about the clock handlers: omap2_dflt_clk_enable happens to be the > handler for all controllable clocks but could that change in the > future? Looks like there is cpuidle34xx using cpuidle framework on specific boards only. And pm34xx.c and others override pm_idle and use the same low level functions to reduce power consumption as cpuidle34xx. Ideally pm34xx.c (and others) would not override pm_idle, but register as a cpuidle driver. Then the idle events would be tracked by the cpuidle subsystem automatically (with my latest patches). But this would be a more intrusive change (are there efforts to do that?). Even if it should happen at some point, adding some additional events for people to better debug/monitor the stuff now does not hurt. Thomas