Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758102Ab3DAHJA (ORCPT ); Mon, 1 Apr 2013 03:09:00 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:54246 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757058Ab3DAHI7 (ORCPT ); Mon, 1 Apr 2013 03:08:59 -0400 Message-ID: <5159320C.4050903@linux.vnet.ibm.com> Date: Mon, 01 Apr 2013 12:36:52 +0530 From: Preeti U Murthy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 MIME-Version: 1.0 To: Joonsoo Kim CC: Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org, Mike Galbraith , Paul Turner , Alex Shi , Vincent Guittot , Morten Rasmussen , Namhyung Kim Subject: Re: [PATCH 4/5] sched: don't consider upper se in sched_slice() References: <1364457537-15114-1-git-send-email-iamjoonsoo.kim@lge.com> <1364457537-15114-5-git-send-email-iamjoonsoo.kim@lge.com> <51553EF5.90702@linux.vnet.ibm.com> <20130401040820.GA12015@lge.com> In-Reply-To: <20130401040820.GA12015@lge.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 13040107-0260-0000-0000-000002BEC9BA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1277 Lines: 40 Hi Joonsoo, On 04/01/2013 09:38 AM, Joonsoo Kim wrote: > Hello, Preeti. > >> >> Ideally the children's cpu share must add upto the parent's share. >> > > I don't think so. > > We should schedule out the parent tg if 5ms is over. As we do so, we can > fairly distribute time slice to every tg within short term. If we add > the children's cpu share upto the parent's, the parent tg may have > large time slice, so it cannot be preempted easily. There may be a latency > problem if there are many tgs. In the case where the #running < sched_nr_latency, the children's sched_slices add up to the parent's. A rq with two tgs,each with 3 tasks. Each of these tasks have a sched slice of [(sysctl_sched_latency / 3) / 2] as of the present implementation. The sum of the above sched_slice of all tasks of a tg will lead to the sched_slice of its parent: sysctl_sched_latency / 2 This breaks when the nr_running on each tg > sched_nr_latency. However I don't know if this is a good thing or a bad thing. Regards Preeti U Murthy -- 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/