From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753837AbbIHIjE (ORCPT ); Tue, 8 Sep 2015 04:39:04 -0400 Received: from blu004-omc1s38.hotmail.com ([65.55.116.49]:62330 "EHLO BLU004-OMC1S38.hotmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751658AbbIHIi7 (ORCPT ); Tue, 8 Sep 2015 04:38:59 -0400 X-TMN: [UEPyFUgTau5CZl+js7NpCMkmZ+wodC9z] X-Originating-Email: [wanpeng.li@hotmail.com] Message-ID: Subject: Re: [PATCH] sched: fix lose fair sleeper bonus in switch_to_fair() To: Byungchul Park References: <20150908052817.GD6455@byungchulpark-X58A-UD3R> <20150908061426.GE6455@byungchulpark-X58A-UD3R> <20150908063240.GF6455@byungchulpark-X58A-UD3R> <20150908071139.GI6455@byungchulpark-X58A-UD3R> <20150908075728.GJ6455@byungchulpark-X58A-UD3R> <20150908082239.GK6455@byungchulpark-X58A-UD3R> CC: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, yuyang.du@intel.com From: Wanpeng Li Date: Tue, 8 Sep 2015 16:38:52 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150908082239.GK6455@byungchulpark-X58A-UD3R> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 08 Sep 2015 08:38:57.0509 (UTC) FILETIME=[CD65D150:01D0EA11] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/8/15 4:22 PM, Byungchul Park wrote: > On Tue, Sep 08, 2015 at 04:04:49PM +0800, Wanpeng Li wrote: >>>> However, if se->vruntime -= cfs_rq->min_vruntime is positive, the >>>> behavior is different after your patch. e.g. se->vruntime(the >>>> relative vruntime in switched_to_fair()) < min_vruntime - >>>> sysctl_sched_latency/2 >>>> >>>> before your patch: >>>> >>>> se->vruntime = min_vruntime - sysctl_sched_latency/2 (place_entity()) >>> my patch is based on ff277d4 commit at tip/sched/core. >>> >>> there's no change between before and after. >>> >>> check it please. >>> >>> and this logic seems to be no problem to me. :( >> Your logic will lose fair sleeper bonus in the scenario which I pointed out. > i mean in ff277d4 commit: Please include the commit subject when you point out a commit, do you mean this one? commit ff277d4250fe715b6666219b1a3423b863418794 Author: Andrea Parri Date: Wed Aug 5 15:56:19 2015 +0200 sched/deadline: Fix comment in enqueue_task_dl() The "dl_boosted" flag is set by comparing *absolute* deadlines (c.f., rt_mutex_setprio()). What's the relationship w/ this patch? Regards, Wanpeng Li > > se->vruntime += cfs->min_vruntime (switched_to_fair()) > se->vruntime = se->vruntime or bonused value (place_entity()) > > after my patch: > > se->vruntime += cfs->min_vruntime (switched_to_fair()) > se->vruntime = se->vruntime or bonused value (place_entity()) > > --- > > SAME!!! > > in addtion, se->vruntime already had a bonused value if eligible, > when it was detached from cfs_rq. > >>>> after your patch: >>>> >>>> se->vruntime += cfs->min_vruntime (switched_to_fair()) >>>> se->vruntime = se->vruntime (place_entity()) >>>> >>>> >>>> Regards, >>>> Wanpeng Li >>>> >>>> -- >>>> 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/ >> -- >> 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/