Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755887AbXJARJc (ORCPT ); Mon, 1 Oct 2007 13:09:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752393AbXJARJZ (ORCPT ); Mon, 1 Oct 2007 13:09:25 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:33325 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752008AbXJARJY (ORCPT ); Mon, 1 Oct 2007 13:09:24 -0400 Date: Mon, 1 Oct 2007 19:09:03 +0200 From: Ingo Molnar To: Chris Friesen Cc: Jarek Poplawski , Nick Piggin , David Schwartz , linux-kernel@vger.kernel.org, Mike Galbraith , Peter Zijlstra , Martin Michlmayr , Srivatsa Vaddagiri , Stephen Hemminger Subject: Re: Network slowdown due to CFS Message-ID: <20071001170903.GA2492@elte.hu> References: <20070926133138.GA23187@elte.hu> <20070927133123.GA6901@elte.hu> <20070927144228.GC2431@ff.dom.local> <200709281610.00682.nickpiggin@yahoo.com.au> <20071001084356.GA1866@ff.dom.local> <20071001162507.GA22791@elte.hu> <47012696.2010606@nortel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47012696.2010606@nortel.com> User-Agent: Mutt/1.5.14 (2007-02-12) 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=3.1.7-deb -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0006] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1204 Lines: 35 * Chris Friesen wrote: > Ingo Molnar wrote: > > >But, because you assert it that it's risky to "criticise sched_yield() > >too much", you sure must know at least one real example where it's right > >to use it (and cite the line and code where it's used, with > >specificity)? > > It's fine to criticise sched_yield(). I agree that new apps should > generally be written to use proper completion mechanisms or to wait > for specific events. yes. > However, there are closed-source and/or frozen-source apps where it's > not practical to rewrite or rebuild the app. Does it make sense to > break the behaviour of all of these? See the background and answers to that in: http://lkml.org/lkml/2007/9/19/357 http://lkml.org/lkml/2007/9/19/328 there's plenty of recourse possible to all possible kinds of apps. Tune the sysctl flag in one direction or another, depending on which behavior the app is expecting. 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/