From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937671AbXG0RRP (ORCPT ); Fri, 27 Jul 2007 13:17:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765835AbXG0RQ4 (ORCPT ); Fri, 27 Jul 2007 13:16:56 -0400 Received: from mx1.redhat.com ([66.187.233.31]:44530 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937619AbXG0RQz (ORCPT ); Fri, 27 Jul 2007 13:16:55 -0400 Message-ID: <46AA287D.8070200@redhat.com> Date: Fri, 27 Jul 2007 13:16:45 -0400 From: Chris Snook User-Agent: Thunderbird 2.0.0.0 (X11/20070419) MIME-Version: 1.0 To: Tong Li CC: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [RFC] scheduler: improve SMP fairness in CFS References: <20070725110159.GA15076@elte.hu> <20070725120358.GA30755@elte.hu> <20070725192442.GC4463@elte.hu> <20070726213154.GA26569@elte.hu> <1185487225.3122.11.camel@tongli.jf.intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tong Li wrote: > I'd like to clarify that I'm not trying to push this particular code to > the kernel. I'm a researcher. My intent was to point out that we have a > problem in the scheduler and my dwrr algorithm can potentially help fix > it. The patch itself was merely a proof-of-concept. I'd be thrilled if > the algorithm can be proven useful in the real world. I appreciate the > people who have given me comments. Since then, I've revised my > algorithm/code. Now it doesn't require global locking but retains strong > fairness properties (which I was able to prove mathematically). Thanks for doing this work. Please don't take the implementation criticism as a lack of appreciation for the work. I'd like to see dwrr in the scheduler, but I'm skeptical that re-introducing expired runqueues is the most efficient way to do it. Given the inherently controversial nature of scheduler code, particularly that which attempts to enforce fairness, perhaps a concise design document would help us come to an agreement about what we think the scheduler should do and what tradeoffs we're willing to make to do those things. Do you have a design document we could discuss? -- Chris