Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932695AbbFWQtw (ORCPT ); Tue, 23 Jun 2015 12:49:52 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([146.101.78.143]:60443 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754734AbbFWQto convert rfc822-to-8bit (ORCPT ); Tue, 23 Jun 2015 12:49:44 -0400 Message-ID: <55898E28.7040706@arm.com> Date: Tue, 23 Jun 2015 17:49:44 +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" , "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 v9 1/4] sched: Remove rq's runnable avg References: <1435018085-7004-1-git-send-email-yuyang.du@intel.com> <1435018085-7004-2-git-send-email-yuyang.du@intel.com> In-Reply-To: <1435018085-7004-2-git-send-email-yuyang.du@intel.com> X-OriginalArrivalTime: 23 Jun 2015 16:49:39.0804 (UTC) FILETIME=[9890C1C0:01D0ADD4] X-MC-Unique: GHchAo_WThyX1OwJ78rQkw-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: 1646 Lines: 41 On 23/06/15 01:08, Yuyang Du wrote: > The per-rq runnable averages (rq->avg) was introduced by Ben with this commit: > > commit 18bf2805d9b30cb823d4919b42cd230f59c7ce1f > Author: Ben Segall > Date: Thu Oct 4 12:51:20 2012 +0200 > > sched: Maintain per-rq runnable averages > > Since runqueues do not have a corresponding sched_entity we instead embed a > sched_avg structure directly. > > Signed-off-by: Ben Segall > Reviewed-by: Paul Turner > Signed-off-by: Peter Zijlstra > Link: http://lkml.kernel.org/r/20120823141506.442637130@google.com > Signed-off-by: Ingo Molnar > > With CONFIG_FAIR_GROUP_SCHED=y, the rq->avg (runnable_avg_sum, avg_period) is > used to calc the contrib in __update_tg_runnable_avg() for the root group. > > But the root group's load data is never consumed since its merge into kernel > in 2012. The basic reason is we have just one root group, and it is > meaningless to give it weight. As the extra code is in the scheduler's > hot path, so it is better to remove it. > > Signed-off-by: Yuyang Du Reviewed-by: Dietmar Eggemann Tested-by: Dietmar Eggemann There is an additional clean-up possible since idle_[enter|exit]_fair() are empty now. [...] -- 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/