From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756412AbXD2MJR (ORCPT ); Sun, 29 Apr 2007 08:09:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756411AbXD2MJR (ORCPT ); Sun, 29 Apr 2007 08:09:17 -0400 Received: from nz-out-0506.google.com ([64.233.162.237]:58474 "EHLO nz-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756412AbXD2MJP (ORCPT ); Sun, 29 Apr 2007 08:09:15 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=pDqAv5Mee9bhRZcnsubuwASzwZhYNgTe6vQO1RuyiidT4JOC1oUi61dOyOBF3twLRUBrH6lhLrO1AcI51b6iWK/S4Xx4SXJsH9RKX4nasA7hygUK34r3p4mIsOYMVwxU8Yg/zgBAtaEU/Az6Xw97kwrNqkfD1/2OxhKCAHQYAEY= Message-ID: <4d8e3fd30704290509r79b7fc47i17ce286a43564259@mail.gmail.com> Date: Sun, 29 Apr 2007 14:09:14 +0200 From: "Paolo Ciarrocchi" To: "Con Kolivas" Subject: Re: [patch] CFS scheduler, -v6 Cc: "Willy Tarreau" , "Thomas Gleixner" , "Ingo Molnar" , "Kasper Sandberg" , "Linus Torvalds" , "Andrew Morton" , "Gene Heskett" , linux-kernel@vger.kernel.org, "Nick Piggin" , "Mike Galbraith" , "Arjan van de Ven" , "Peter Williams" , caglar@pardus.org.tr, "Mark Lord" , "Zach Carter" , buddabrod In-Reply-To: <200704292146.15653.kernel@kolivas.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200704261041.04838.gene.heskett@gmail.com> <1177842654.5791.85.camel@localhost.localdomain> <20070429111159.GH23638@1wt.eu> <200704292146.15653.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 4/29/07, Con Kolivas wrote: > On Sunday 29 April 2007 21:11, Willy Tarreau wrote: > > On Sun, Apr 29, 2007 at 12:30:54PM +0200, Thomas Gleixner wrote: > > > Willy, > > > > > > On Sun, 2007-04-29 at 09:16 +0200, Willy Tarreau wrote: > > > > In fact, what I'd like to see in 2.6.22 is something better for > > > > everybody and with *no* regression, even if it's not perfect. I had the > > > > feeling that SD matched that goal right now, except for Mike who has > > > > not tested recent versions. Don't get me wrong, I still think that CFS > > > > is a more interesting long-term target. But it may require more time to > > > > satisfy everyone. At least with one of them in 2.6.22, we won't waste > > > > time comparing to current mainline. > > > > > > Oh no, we really do _NOT_ want to throw SD or anything else at mainline > > > in a hurry just for not wasting time on comparing to the current > > > scheduler. > > > > It is not about doing it in a hurry. I see SD as a small yet efficient > > update to current scheduler. It's not perfect, probably not much extensible > > but the risks of breaking anything are small given the fact that it does > > not change much of the code or behaviour. > > > > IMHO, it is something which can provide users with a useful update while > > leaving us with some more time to carefully implement the features of CFS > > one at a time, and if it requires 5 versions, it's not a problem. > > > > > I agree that CFS is the more interesting target and I prefer to push the > > > more interesting one even if it takes a release cycle longer. The main > > > reason for me is the design of CFS. Even if it is not really modular > > > right now, it is not rocket science to make it fully modular. > > > > > > Looking at the areas where people work on, e.g. containers, resource > > > management, cpu isolation, fully tickless systems ...., we really need > > > to go into that direction, when we want to avoid permanent tinkering in > > > the core scheduler code for the next five years. > > > > > > As a sidenote: I really wonder if anybody noticed yet, that the whole > > > CFS / SD comparison is so ridiculous, that it is not even funny anymore. > > > > Contrarily to most people, I don't see them as competitors. I see SD as > > a first step with a low risk of regression, and CFS as an ultimate > > solution relying on a more solid framework. > > > > > CFS modifies the scheduler and nothing else, SD fiddles all over the > > > kernel in interesting ways. > > > > Hmmm I guess you confused both of them this time. CFS touches many places, > > which is why I think the testing coverage is still very low. SD can be > > tested faster. My real concern is : are there still people observing > > regressions with it ? If yes, they should be fixed before even being > > merged. If no, why not merge it as a fix for the many known corner cases > > of current scheduler ? After all, it's already in -mm. > > > > Willy > > Willy, you're making far too much sense. Are you replying to the correct > mailing list? FWIW, I strongly agree with Willy. Ciao, -- Paolo "Tutto cio' che merita di essere fatto,merita di essere fatto bene" Philip Stanhope IV conte di Chesterfield