From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1766821AbXDSPoD (ORCPT ); Thu, 19 Apr 2007 11:44:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1766823AbXDSPoB (ORCPT ); Thu, 19 Apr 2007 11:44:01 -0400 Received: from x35.xmailserver.org ([64.71.152.41]:4297 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1766821AbXDSPoA (ORCPT ); Thu, 19 Apr 2007 11:44:00 -0400 X-AuthUser: davidel@xmailserver.org Date: Thu, 19 Apr 2007 08:43:41 -0700 (PDT) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Ingo Molnar cc: Linus Torvalds , Matt Mackall , Nick Piggin , William Lee Irwin III , Peter Williams , Mike Galbraith , Con Kolivas , ck list , Bill Huey , Linux Kernel Mailing List , Andrew Morton , Arjan van de Ven , Thomas Gleixner Subject: Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS] In-Reply-To: <20070419080053.GA4106@elte.hu> Message-ID: References: <20070418055525.GS11115@waste.org> <20070418152355.GU11115@waste.org> <20070418174945.GA7930@elte.hu> <20070418175936.GA11980@elte.hu> <20070418214816.GA10902@elte.hu> <20070419080053.GA4106@elte.hu> X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Apr 2007, Ingo Molnar wrote: > i disagree that the user 'would expect' this. Some users might. Others > would say: 'my 10-thread rendering engine is more important than a > 1-thread job because it's using 10 threads for a reason'. And the CFS > feedback so far strengthens this point: the default behavior of treating > the thread as a single scheduling (and CPU time accounting) unit works > pretty well on the desktop. > > think about it in another, 'kernel policy' way as well: we'd like to > _encourage_ more parallel user applications. Hurting them by accounting > all threads together sends the exact opposite message. There are counter argouments too. Like, not every user knows if a certain process is MT or not. I agree though that doing accounting and fairness at a depth lower then USER is messy, and not only for performance. - Davide