Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752213AbaFDR1S (ORCPT ); Wed, 4 Jun 2014 13:27:18 -0400 Received: from casper.infradead.org ([85.118.1.10]:47820 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751410AbaFDR1R (ORCPT ); Wed, 4 Jun 2014 13:27:17 -0400 Date: Wed, 4 Jun 2014 19:27:12 +0200 From: Peter Zijlstra To: Morten Rasmussen Cc: "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" , "mingo@kernel.org" , "rjw@rjwysocki.net" , "vincent.guittot@linaro.org" , "daniel.lezcano@linaro.org" , "preeti@linux.vnet.ibm.com" , Dietmar Eggemann Subject: Re: [RFC PATCH 06/16] arm: topology: Define TC2 sched energy and provide it to scheduler Message-ID: <20140604172712.GJ13930@laptop.programming.kicks-ass.net> References: <1400869003-27769-1-git-send-email-morten.rasmussen@arm.com> <1400869003-27769-7-git-send-email-morten.rasmussen@arm.com> <20140603115015.GZ11096@twins.programming.kicks-ass.net> <20140604160230.GS29593@e103034-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140604160230.GS29593@e103034-lin> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 04, 2014 at 05:02:30PM +0100, Morten Rasmussen wrote: > On Tue, Jun 03, 2014 at 12:50:15PM +0100, Peter Zijlstra wrote: > > On Fri, May 23, 2014 at 07:16:33PM +0100, Morten Rasmussen wrote: > > > +static struct capacity_state cap_states_cluster_a7[] = { > > > + /* Cluster only power */ > > > + { .cap = 358, .power = 2967, }, /* 350 MHz */ > > > + { .cap = 410, .power = 2792, }, /* 400 MHz */ > > > + { .cap = 512, .power = 2810, }, /* 500 MHz */ > > > + { .cap = 614, .power = 2815, }, /* 600 MHz */ > > > + { .cap = 717, .power = 2919, }, /* 700 MHz */ > > > + { .cap = 819, .power = 2847, }, /* 800 MHz */ > > > + { .cap = 922, .power = 3917, }, /* 900 MHz */ > > > + { .cap = 1024, .power = 4905, }, /* 1000 MHz */ > > > + }; > > > > So one thing I remember was that we spoke about restricting this to > > frequency levels where the voltage changed. > > > > Because voltage jumps were the biggest factor to energy usage. > > > > Any word on that? > > Since we don't drive P-state changes from the scheduler, I think we > could leave out P-states from the table without too much trouble. Good > point. Well, we eventually want to go there I think. Although we still needed to come up with something for Intel, because I'm not at all sure how all that works. > TC2 is an early development platform and somewhat different from what > you find in end user products. TC2 actually uses the same voltage for > all states except the highest 2-3 states. That is not typical. The > voltage is typically slightly different for each state, however, the > difference get bigger for higher P-states. We could probably get away > with representing multiple states as one in the energy model if the > voltage change is minimal. So while I don't mind the full table, esp. if its fairly easy to generate using that tool you spoke about, I just wondered if it made sense to somewhat reduce it. Now that I look at the actual .power values, you can indeed see that all except the last two are pretty much similar in power usage. On that, is that fluctuation measurement noise, or is that stable? -- 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/