From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752901AbXCLUjS (ORCPT ); Mon, 12 Mar 2007 16:39:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752903AbXCLUjS (ORCPT ); Mon, 12 Mar 2007 16:39:18 -0400 Received: from mail09.syd.optusnet.com.au ([211.29.132.190]:41409 "EHLO mail09.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752901AbXCLUjQ (ORCPT ); Mon, 12 Mar 2007 16:39:16 -0400 From: Con Kolivas To: Mike Galbraith Subject: Re: [PATCH][RSDL-mm 0/7] RSDL cpu scheduler for 2.6.21-rc3-mm2 Date: Tue, 13 Mar 2007 07:38:18 +1100 User-Agent: KMail/1.9.5 Cc: Ingo Molnar , linux kernel mailing list , ck list , Linus Torvalds , Andrew Morton References: <200703111457.17624.kernel@kolivas.org> <200703130549.47058.kernel@kolivas.org> <1173730314.6431.30.camel@Homer.simpson.net> In-Reply-To: <1173730314.6431.30.camel@Homer.simpson.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200703130738.19034.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 13 March 2007 07:11, Mike Galbraith wrote: > On Tue, 2007-03-13 at 05:49 +1100, Con Kolivas wrote: > > On Tuesday 13 March 2007 01:34, 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. > > > > Again I think your test is not a valid testcase. Why use two threads for > > your encoding with one cpu? Is that what other dedicated desktop OSs > > would do? > > The testcase is perfectly valid. My buddies box has two full cores, so > we used two encoders such that whatever bandwidth is not being actively > consumed by more important things gets translated into mp3 encoding. > > How would you go about ensuring that there won't be any cycles wasted? > > _My_ box has 1 core that if fully utilized translates to 1.2 cores.. or > whatever, depending on the phase of the moon. But no matter, logical vs > physical cpu argument is pure hand-waving. What really matters here is > the bottom line: your fair scheduler ignores the very real requirements > of interactivity. Definitely not. It does not give unfair cpu towards interactive tasks. That's a very different argument. > > And let's not lose sight of things with this one testcase. > > > > RSDL fixes > > - every starvation case > > - all fairness isssues > > - is better 95% of the time on the desktop > > I don't know where you got that 95% number from. For the most part, the > existing scheduler does well. If it sucked 95% of the time, it would > have been shredded a long time ago. Check the number of feedback reports. I don't feel petty enough to count them personally to give you an accuracte percentage. > > If we fix 95% of the desktop and worsen 5% is that bad given how much > > else we've gained in the process? > > Killing the known corner case starvation scenarios is wonderful, but > let's not just pretend that interactive tasks don't have any special > requirements. Now you're really making a stretch of things. Where on earth did I say that interactive tasks don't have special requirements? It's a fundamental feature of this scheduler that I go to great pains to get them as low latency as possible and their fair share of cpu despite having a completely fair cpu distribution. > -Mike -- -ck