Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755449AbaFKLDF (ORCPT ); Wed, 11 Jun 2014 07:03:05 -0400 Received: from mail-ve0-f169.google.com ([209.85.128.169]:42883 "EHLO mail-ve0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751050AbaFKLDD (ORCPT ); Wed, 11 Jun 2014 07:03:03 -0400 Date: Wed, 11 Jun 2014 07:02:51 -0400 From: Eduardo Valentin To: Nicolas Pitre Cc: Morten Rasmussen , Ingo Molnar , Peter Zijlstra , Yuyang Du , Dirk Brandewie , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" , "vincent.guittot@linaro.org" , "daniel.lezcano@linaro.org" , "preeti@linux.vnet.ibm.com" , Dietmar Eggemann , "len.brown@intel.com" , "jacob.jun.pan@linux.intel.com" Subject: Re: [RFC PATCH 06/16] arm: topology: Define TC2 sched energy and provide it to scheduler Message-ID: <20140611110251.GA6702@developer> References: <539086B3.2010804@gmail.com> <20140605202930.GA15484@intel.com> <20140606080543.GR6758@twins.programming.kicks-ass.net> <20140606003520.GB22261@intel.com> <20140606105036.GQ3213@twins.programming.kicks-ass.net> <20140606121305.GA8571@gmail.com> <20140606122740.GA9318@gmail.com> <20140609082739.GY29593@e103034-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Mon, Jun 09, 2014 at 09:22:49AM -0400, Nicolas Pitre wrote: > On Mon, 9 Jun 2014, Morten Rasmussen wrote: > > > On Sat, Jun 07, 2014 at 03:33:58AM +0100, Nicolas Pitre wrote: > > > On Fri, 6 Jun 2014, Ingo Molnar wrote: > > > > > > > In any case, even with turbo frequencies, switching power use is > > > > probably an order of magnitude higher than leakage current power use, > > > > on any marketable chip, so we should concentrate on being able to > > > > cover this first order effect (P/work ~ V^2), before considering any > > > > second order effects (leakage current). > > > > > > Just so that people are aware... We'll have to introduce thermal > > > constraint management into the scheduler mix as well at some point. > > > Right now what we have is an ad hoc subsystem that simply monitors > > > temperature and apply crude cooling strategies when some thresholds are > > > met. But a better strategy would imply thermal "provisioning". > > > > There is already work going on to improve thermal management: > > > > http://lwn.net/Articles/599598/ > > > > The proposal is based on power/energy models (too). The goal is to Can you please point me to the other piece of code which is using power/energy models too? We are considering having these models within the thermal software compoenents. But if we already have more than one user, might be worth considering a separate API. > > allocate power intelligently based on performance requirements. > > Ah, great! I missed that. > > > While it is related to energy-aware scheduling and I fully agree that it > > is something we need to consider, I think it is worth developing the two > > ideas in parallel and look at sharing things like the power model later > > once things mature. Energy-aware scheduling is complex enough on its > > own to keep us entertained for a while :-) > > Absolutely. This is why I said "at some point". > > > Nicolas > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/