Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755158AbbFSS1j (ORCPT ); Fri, 19 Jun 2015 14:27:39 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([146.101.78.143]:35731 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753174AbbFSS1a convert rfc822-to-8bit (ORCPT ); Fri, 19 Jun 2015 14:27:30 -0400 Message-ID: <55845F0C.8050504@arm.com> Date: Fri, 19 Jun 2015 19:27:24 +0100 From: Dietmar Eggemann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Yuyang Du , "mingo@kernel.org" , "peterz@infradead.org" , "linux-kernel@vger.kernel.org" CC: "pjt@google.com" , "bsegall@google.com" , Morten Rasmussen , "vincent.guittot@linaro.org" , "arjan.van.de.ven@intel.com" , "len.brown@intel.com" , "rafael.j.wysocki@intel.com" , "fengguang.wu@intel.com" , "boqun.feng@gmail.com" , "srikar@linux.vnet.ibm.com" Subject: Re: [PATCH v8 1/4] sched: Remove rq's runnable avg References: <1434396367-27979-1-git-send-email-yuyang.du@intel.com> <1434396367-27979-2-git-send-email-yuyang.du@intel.com> In-Reply-To: <1434396367-27979-2-git-send-email-yuyang.du@intel.com> X-OriginalArrivalTime: 19 Jun 2015 18:27:24.0951 (UTC) FILETIME=[96D02A70:01D0AABD] X-MC-Unique: 9Q72vZTDRqOyWK5FtOhvqw-1 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 852 Lines: 25 Hi Yuyang, On 15/06/15 20:26, Yuyang Du wrote: > The current rq->avg is not used at all since its merge into kernel, > and the code is in the scheduler's hot path, so remove it. are you sure that this is the case? I was always under the impression that w/ CONFIG_FAIR_GROUP_SCHED=y rq->avg (runnable_avg_sum, avg_period) is used to calculate contrib in __update_tg_runnable_avg() for the root group (cfs_rq->tg->css.id = 1). On tg's w/ cfs_rq->tg->css.id > 1, se->avg (runnable_avg_sum, avg_period) is used instead but we simply don't have a tg related se for the root group. IMHO, that's why we have this rq::avg. I understand that w/ the second patch in your series you don't need rq::avg any more. [...] -- Dietmar -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/