Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753808AbZIHHId (ORCPT ); Tue, 8 Sep 2009 03:08:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753732AbZIHHId (ORCPT ); Tue, 8 Sep 2009 03:08:33 -0400 Received: from mail-px0-f196.google.com ([209.85.216.196]:40166 "EHLO mail-px0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753636AbZIHHIc (ORCPT ); Tue, 8 Sep 2009 03:08:32 -0400 Subject: Re: question on sched-rt group allocation cap: sched_rt_runtime_us Mime-Version: 1.0 (Apple Message framework v1075.2) Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes From: Anirban Sinha In-Reply-To: Date: Tue, 8 Sep 2009 00:08:31 -0700 Cc: Anirban Sinha Content-Transfer-Encoding: 7bit Message-Id: <9039A647-41AF-43C0-9376-F21E664F61E5@anirban.org> References: <36bbf267-be27-4c9e-b782-91ed32a1dfe9@g1g2000pra.googlegroups.com> <1252218779.6126.17.camel@marge.simson.net> <1252310374.7564.6.camel@twins> To: Anirban Sinha , Peter Zijlstra , Mike Galbraith , linux-kernel@vger.kernel.org, Ingo Molnar , Dario Faggioli X-Mailer: Apple Mail (2.1075.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1896 Lines: 59 On 2009-09-07, at 9:42 AM, Anirban Sinha wrote: > > > > -----Original Message----- > From: Peter Zijlstra [mailto:a.p.zijlstra@chello.nl] > Sent: Mon 9/7/2009 12:59 AM > To: Mike Galbraith > Cc: Anirban Sinha; Lucas De Marchi; linux-kernel@vger.kernel.org; > Ingo Molnar > Subject: Re: question on sched-rt group allocation cap: > sched_rt_runtime_us > > On Sun, 2009-09-06 at 08:32 +0200, Mike Galbraith wrote: > > On Sat, 2009-09-05 at 19:32 -0700, Ani wrote: > > > On Sep 5, 3:50 pm, Lucas De Marchi > wrote: > > > > > > > > Indeed. I've tested this same test program in a single core > machine and it > > > > produces the expected behavior: > > > > > > > > rt_runtime_us / rt_period_us % loops executed in SCHED_OTHER > > > > 95% 4.48% > > > > 60% 54.84% > > > > 50% 86.03% > > > > 40% OTHER completed first > > > > > > > > > > Hmm. This does seem to indicate that there is some kind of > > > relationship with SMP. So I wonder whether there is a way to > turn this > > > 'RT bandwidth accumulation' heuristic off. > > > > No there isn't.. > > Actually there is, use cpusets to carve the system into partitions. hmm. ok. I looked at the code a little bit. It seems to me that the 'borrowing' of RT runtimes occurs only from rt runqueues belonging to the same root domain. And partition_sched_domains() is the only external interface that can be used to create root domain out of a CPU set. But then I think it needs to have CGROUPS/USER groups enabled? Right? --Ani > > > -- 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/