From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933614AbdEVNfE (ORCPT ); Mon, 22 May 2017 09:35:04 -0400 Received: from mail-pf0-f176.google.com ([209.85.192.176]:36741 "EHLO mail-pf0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933201AbdEVNfC (ORCPT ); Mon, 22 May 2017 09:35:02 -0400 Date: Mon, 22 May 2017 21:34:52 +0800 From: Leo Yan To: Sudeep Holla Cc: Daniel Lezcano , rjw@rjwysocki.net, lorenzo.pieralisi@arm.com, "open list:CPUIDLE DRIVERS" , open list Subject: Re: [PATCH] ARM: cpuidle: Support asymmetric idle definition Message-ID: <20170522133452.GC9325@leoy-ThinkPad-T440> References: <1495212343-24873-1-git-send-email-daniel.lezcano@linaro.org> <850fab54-d6e6-7b4c-631a-f4ee658c96fa@arm.com> <45754d0a-6a98-2987-74ed-429926d89cbc@arm.com> <3ce7048e-6d9d-9e46-a6fb-4d3263231536@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3ce7048e-6d9d-9e46-a6fb-4d3263231536@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 Hi Sudeep, On Mon, May 22, 2017 at 02:02:12PM +0100, Sudeep Holla wrote: [...] > >>>> On 19/05/17 17:45, Daniel Lezcano wrote: > >>>>> Some hardware have clusters with different idle states. The current code does > >>>>> not support this and fails as it expects all the idle states to be identical. > >>>>> > >>>>> Because of this, the Mediatek mtk8173 had to create the same idle state for a > >>>>> big.Little system and now the Hisilicon 960 is facing the same situation. > >>>>> > >>>> > >>>> While I agree the we don't support them today, it's better to benchmark > >>>> and record/compare the gain we get with the support for cluster based > >>>> idle states. > >>> > >>> Sorry, I don't get what you are talking about. What do you want to > >>> benchmark ? Cluster idling ? > >>> > >> > >> OK, I was not so clear. I had a brief chat with Lorenzo, we have few > >> reason to have this support: > >> 1. Different number of states between clusters > >> 2. Different latencies(this is the one I was referring above, generally > >> we keep worst case timings here and wanted to see if any platform > >> measured improvements with different latencies in the idle states) > > > > I don't see the point. Are you putting into question the big little design? > > > > Not exactly. Since they are generally worst case number, I wanted to > check if someone saw real benefit with 2 different set of values. > Anyways that's not important or blocking, just raised a point, so that > we can stick some benchmarking results with this. In case you are interesting for Hikey960 idle states, you could see the two clustsers have different idle states: http://termbin.com/d7ed [...] Thanks, Leo Yan