Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932514AbbFVGSU (ORCPT ); Mon, 22 Jun 2015 02:18:20 -0400 Received: from mga03.intel.com ([134.134.136.65]:60694 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752443AbbFVGSM (ORCPT ); Mon, 22 Jun 2015 02:18:12 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,657,1427785200"; d="scan'208";a="592333004" Date: Mon, 22 Jun 2015 06:26:01 +0800 From: Yuyang Du To: Dietmar Eggemann Cc: "mingo@kernel.org" , "peterz@infradead.org" , "linux-kernel@vger.kernel.org" , "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 v8 1/4] sched: Remove rq's runnable avg Message-ID: <20150621222601.GB3933@intel.com> References: <1434396367-27979-1-git-send-email-yuyang.du@intel.com> <1434396367-27979-2-git-send-email-yuyang.du@intel.com> <55845F0C.8050504@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55845F0C.8050504@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 Content-Length: 1125 Lines: 31 Hi Dietmar, On Fri, Jun 19, 2015 at 07:27:24PM +0100, Dietmar Eggemann wrote: > 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. Yes, I agree. But the root group's avg is not useful anyway. If it is, we sure should keep it. > I understand that w/ the second patch in your series you don't need > rq::avg any more. And the rq->avg can be replaced by the root cfs_rq's util_avg, too. Thanks, Yuyang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/