Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932782Ab3DDGu7 (ORCPT ); Thu, 4 Apr 2013 02:50:59 -0400 Received: from e23smtp02.au.ibm.com ([202.81.31.144]:51663 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756429Ab3DDGu6 (ORCPT ); Thu, 4 Apr 2013 02:50:58 -0400 Message-ID: <515D2240.9060501@linux.vnet.ibm.com> Date: Thu, 04 Apr 2013 12:18:32 +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> <5159320C.4050903@linux.vnet.ibm.com> <20130402022556.GD16699@lge.com> <515A64BB.5050005@linux.vnet.ibm.com> <20130402092647.GE16699@lge.com> <515B163B.8050509@linux.vnet.ibm.com> <20130404004231.GA10683@lge.com> In-Reply-To: <20130404004231.GA10683@lge.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 13040406-5490-0000-0000-00000338FF21 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1286 Lines: 39 Hi Joonsoo, On 04/04/2013 06:12 AM, Joonsoo Kim wrote: > Hello, Preeti. > > So, how about extending a sched_period with rq->nr_running, instead of > cfs_rq->nr_running? It is my quick thought and I think that we can ensure > to run atleast once in this extending sched_period. Yeah this seems to be correct.This would ensure sched_min_granularity also. So then in the scenarion where there are 2 tgs in a runqueue with 10 tasks each,when we calculate the sched_slice of any task,the __sched_period() would return 4*20 = 80ms. The sched_slice of each of the task would be 80/20 = 4ms. But what about the sched_slice of each task group? How would that be calculated then? Let us take the above example and walk through this problem.This would probably help us spot the issues involved with this. > And, do we leave a problem if we cannot guaranteed atleast once property? This would depend on the results of the benchmarks with the changes.I am unable to comment on this off the top of my head. Thank you 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/