From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765744AbXG2RHL (ORCPT ); Sun, 29 Jul 2007 13:07:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764497AbXG2RHA (ORCPT ); Sun, 29 Jul 2007 13:07:00 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:45616 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764417AbXG2RG7 (ORCPT ); Sun, 29 Jul 2007 13:06:59 -0400 Date: Sun, 29 Jul 2007 19:06:41 +0200 From: Ingo Molnar To: Kasper Sandberg Cc: Linus Torvalds , Linux Kernel Mailing List , ck@vds.kolivas.org Subject: Re: SD still better than CFS for 3d ?(was Re: 2.6.23-rc1) Message-ID: <20070729170641.GA26220@elte.hu> References: <1185536610.502.8.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1185536610.502.8.camel@localhost> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7-deb -1.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Kasper Sandberg wrote: > Im still not so keen about this, Ingo never did get CFS to match SD in > smoothness for 3d applications, where my test subjects are quake(s), > world of warcraft via wine, unreal tournament 2004. [...] here's an update: checking whether Wine could be a factor in your problem i just tested latest CFS against latest SD with a 3D game running under Wine: v2.6.22-ck1 versus v2.6.22-cfsv19 (to get the most comparable kernel), using Quake 3 Arena Demo under Wine (0.9.41). Here are the results in a pretty graph: http://people.redhat.com/mingo/misc/cfs-vs-sd-wine-quake.jpg or, in text: 2.6.22-ck1 2.6.22-cfs-v19 ------------------------ ------------------------ quake + 0 loops | 41 fps quake + 0 loops | 41 fps quake + 1 loop | 3 fps quake + 1 loop | 41 fps quake + 2 loops | 2 fps quake + 2 loops | 32 fps quake + 3 loops | 1 fps quake + 3 loops | 24 fps quake + 4 loops | 0 fps quake + 4 loops | 20 fps quake + 5 loops | 0 fps quake + 5 loops | 16 fps Quake3-under-Wine behavior under SD/-ck: framerate breaks down massively during any kind of load. The game is completely unusable with 1 CPU loop running already! Quake3-under-Wine behavior under CFS: framerate goes down gently with load, gameplay remains smooth. Framerate is still pretty acceptable and the game is playable even with a 500% CPU overload. The graph looks good and the framerate reduction goes roughly along the expected 1/n 'fairness curve' - so it all looks pretty healthy. [Note: quake3 keeps its fully 41 fps even with 1 competing loop running on the CPU due to "sleeper fairness".] [ i've re-tested this using other SD and ck versions and other CFS versions such as v2.6.23-rc1 and the results are the same. To get the fps result i started a simple game scene: Single Player / Q3DM1 / I Can Win, turned on the fps display of Quake3, and did not move the player at all, just looked at the framerate that is displayed. (i also tried other scenes and other gameplay sections and they all behave consistently with the above results.) The system was otherwise completely idle. While i trust these numbers take them with a grain of salt, i'm obviously not neutral in this thing :-) ] so Kasper, i'll definitely need your help in tracking down your 3D smoothness problem under CFS. I have the feeling that it could be some odd factor that only hits your system, and once we've tracked that down there will be a simple solution that does not affect the totality of the scheduler. So far only you have reported any 3D game smoothness problem against recent CFS versions. (all 3D feedback has been positive, and that includes a number of gamers as well. Most of the 3D smoothness problems were fixed in CFS v13..v15 and it has not been reported to have regressed since then.) Ingo