From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750893AbXCLSKk (ORCPT ); Mon, 12 Mar 2007 14:10:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750918AbXCLSKk (ORCPT ); Mon, 12 Mar 2007 14:10:40 -0400 Received: from mail16.syd.optusnet.com.au ([211.29.132.197]:37156 "EHLO mail16.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750893AbXCLSKj (ORCPT ); Mon, 12 Mar 2007 14:10:39 -0400 From: Con Kolivas To: Linus Torvalds Subject: Re: [PATCH][RSDL-mm 0/7] RSDL cpu scheduler for 2.6.21-rc3-mm2 Date: Tue, 13 Mar 2007 05:10:05 +1100 User-Agent: KMail/1.9.5 Cc: Mike Galbraith , Ingo Molnar , linux kernel mailing list , ck list , Andrew Morton References: <200703111457.17624.kernel@kolivas.org> <1173710082.6326.49.camel@Homer.simpson.net> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200703130510.05588.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 13 March 2007 02:26, Linus Torvalds wrote: > On Mon, 12 Mar 2007, Mike Galbraith wrote: > > On Mon, 2007-03-12 at 22:23 +1100, Con Kolivas wrote: > > > Mike the cpu is being proportioned out perfectly according to fairness > > > as I mentioned in the prior email, yet X is getting the lower latency > > > scheduling. I'm not sure within the bounds of fairness what more would > > > you have happen to your liking with this test case? > > > > It has been said that "perfection is the enemy of good". The two > > interactive tasks receiving 40% cpu while two niced background jobs > > receive 60% may well be perfect, but it's damn sure not good. > > Well, the real problem is really "server that works on behalf of somebody > else". > > X is just the worst *practical* example of this, since not only is it the > most common such server, it's also a case where people see interactive > issues really easily. > > And the problem is that a lot of clients actually end up doing *more* in > the X server than they do themselves directly. Doing things like showing a > line of text on the screen is a lot more expensive than just keeping track > of that line of text, so you end up with the X server easily being marked > as getting "too much" CPU time, and the clients as being starved for CPU > time. And then you get bad interactive behaviour. > > So "good fairness" really should involve some notion of "work done for > others". It's just not very easy to do.. Instead of assuming it's bad, have you tried RSDL for yourself? Mike is using 2 lame threads for his test case. -- -ck