Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753855AbYH1L33 (ORCPT ); Thu, 28 Aug 2008 07:29:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752146AbYH1L3T (ORCPT ); Thu, 28 Aug 2008 07:29:19 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:54325 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752066AbYH1L3S (ORCPT ); Thu, 28 Aug 2008 07:29:18 -0400 Date: Thu, 28 Aug 2008 13:28:57 +0200 From: Ingo Molnar To: Peter Zijlstra Cc: Andi Kleen , Nick Piggin , Thomas Gleixner , linux-kernel@vger.kernel.org, Stefani Seibold , Dario Faggioli , Max Krasnyansky , Linus Torvalds Subject: Re: [PATCH 6/6] sched: disabled rt-bandwidth by default Message-ID: <20080828112857.GA27534@elte.hu> References: <20080819103301.787700742@chello.nl> <874p57s873.fsf@basil.nowhere.org> <200808272008.16106.nickpiggin@yahoo.com.au> <20080828105408.GA4488@elte.hu> <20080828110923.GL26610@one.firstfloor.org> <1219922353.6443.14.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1219922353.6443.14.camel@twins> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1038 Lines: 25 * Peter Zijlstra wrote: > On Thu, 2008-08-28 at 13:09 +0200, Andi Kleen wrote: > > > Even if the system has multiple CPUs, and even if just a single CPU is > > > fully utilized by an RT task, without the rt-limit the system will still > > > lock up in practice due to various other factors: workqueues and tasks > > > being 'stuck' on CPUs that host an RT hog. > > > > The load balancer will not notice that a particular CPU is busy > > with real time tasks? > > Not currently, working on that though. yeah, that's nice - i tried the earlier iteration of your patch already. It doesnt solve the UP case obviously, nor the case where all CPUs are hogged by RT tasks, nor any other (or future) per CPU aspect of Linux that we have in place currently. Ingo -- 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/