From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754859Ab3BELjz (ORCPT ); Tue, 5 Feb 2013 06:39:55 -0500 Received: from mail.skyhub.de ([78.46.96.112]:39356 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751146Ab3BELjw (ORCPT ); Tue, 5 Feb 2013 06:39:52 -0500 Date: Tue, 5 Feb 2013 12:39:50 +0100 From: Borislav Petkov To: Charles Garcia-Tobin Cc: Viresh Kumar , "Rafael J. Wysocki" , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linaro-dev@lists.linaro.org" , Robin Randhawa , Steve Bannister , Liviu Dudau Subject: Re: [PATCH 0/4] CPUFreq: Implement per policy instances of governors Message-ID: <20130205113950.GG4827@pd.tnic> Mail-Followup-To: Borislav Petkov , Charles Garcia-Tobin , Viresh Kumar , "Rafael J. Wysocki" , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linaro-dev@lists.linaro.org" , Robin Randhawa , Steve Bannister , Liviu Dudau References: <5808458.pvV2iHpBWm@vostro.rjw.lan> <20130204123221.GA22340@pd.tnic> <20130204130403.GD13909@pd.tnic> <20130204133648.GE13909@pd.tnic> <80D6EFE2711DED4189C7C8F0430BFEA86D23D6A80E@BUNGLE.Emea.Arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <80D6EFE2711DED4189C7C8F0430BFEA86D23D6A80E@BUNGLE.Emea.Arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 05, 2013 at 11:29:04AM +0000, Charles Garcia-Tobin wrote: > Actually shooting myself in the foot here, Krait is not such a great > example because although you can use difference between frequencies > you are less likely to use different tunables (not inconceivable > but unlikely). The best examples systems are multi cluster and > hereterogeneous systems, like the recently announced Samsung Exynos 5 > octa http://en.wikipedia.org/wiki/Exynos_(system_on_chip). We will see > more systems like this appearing, sporting low power cores combined > with high performance ones, all running at the same time. I appreciate > this is all very new, but more will come, and the requirement to have > different tunables per cluster is very real. In ARM on our own multi > cluster test chip, using an experimental version of this approach, we > have seen good improvements in power consumption without compromising > performance. Ok, thanks for giving this insight, this is useful. Question: do you need the granularity of that control to be per cpu (with that I mean what linux understands under "cpu," i.e. logical or physical core) or does one governor suffice per a set of cores, or as you call it, a cluster? > (Apologies ahead for any bit my mail server appends, not much I can do > about it) Yeah, my condolences :-) > -- IMPORTANT NOTICE: The contents of this email and any attachments > are confidential and may also be privileged. If you are not the > intended recipient, please notify the sender immediately and do not > disclose the contents to any other person, use it for any purpose, or > store or copy the information in any medium. Thank you. Leaving it in, in case you haven't seen how it looks like :-) -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --