Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762175AbXEPCEX (ORCPT ); Tue, 15 May 2007 22:04:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758544AbXEPCEQ (ORCPT ); Tue, 15 May 2007 22:04:16 -0400 Received: from omta01ps.mx.bigpond.com ([144.140.82.153]:41762 "EHLO omta01ps.mx.bigpond.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757338AbXEPCEQ (ORCPT ); Tue, 15 May 2007 22:04:16 -0400 Message-ID: <464A6698.3080400@bigpond.net.au> Date: Wed, 16 May 2007 12:04:08 +1000 From: Peter Williams User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Ingo Molnar CC: linux-kernel@vger.kernel.org, Linus Torvalds , Andrew Morton , Con Kolivas , Nick Piggin , Mike Galbraith , Arjan van de Ven , Thomas Gleixner , caglar@pardus.org.tr, Willy Tarreau , Gene Heskett , Mark Lord Subject: Re: [patch] CFS scheduler, -v12 References: <20070513153853.GA19846@elte.hu> In-Reply-To: <20070513153853.GA19846@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Authentication-Info: Submitted using SMTP AUTH PLAIN at oaamta06ps.mx.bigpond.com from [138.130.234.53] using ID pwil3058@bigpond.net.au at Wed, 16 May 2007 02:04:13 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2607 Lines: 62 Ingo Molnar wrote: > i'm pleased to announce release -v12 of the CFS scheduler patchset. > > The CFS patch against v2.6.22-rc1, v2.6.21.1 or v2.6.20.10 can be > downloaded from the usual place: > > http://people.redhat.com/mingo/cfs-scheduler/ > > -v12 fixes the '3D bug' that caused trivial latencies in 3D games: it > turns out that the problem was not resulting out of any core quality of > CFS, it was caused by 3D userspace growing dependent on the current > inefficiency of the vanilla scheduler's sys_sched_yield() > implementation, and CFS's "make yield work well" changes broke it. > > Even a simple 3D app like glxgears does a sys_sched_yield() for every > frame it generates (!) on certain 3D cards, which in essence punishes > any scheduler that implements sys_sched_yield() in a sane manner. This > interaction of CFS's yield implementation with this user-space bug could > be the main reason why some testers reported SD to be handling 3D games > better than CFS. (SD uses a yield implementation similar to the vanilla > scheduler.) > > So i've added a yield workaround to -v12, which makes it work similar to > how the vanilla scheduler and SD does it. (Xorg has been notified and > this bug should be fixed there too. This took some time to debug because > the 3D driver i'm using for testing does not use sys_sched_yield().) The > workaround is activated by default so -v12 should work 'out of the box'. > > Mike Galbraith has fixed a bug related to nice levels - the fix should > make negative nice levels more potent again. > > Changes since -v10: > > - nice level calculation fixes (Mike Galbraith) > > - load-balancing improvements (this should fix the SMP performance > problem reported by Michael Gerdau) > > - remove the sched_sleep_history_max tunable. > > - more debugging fields. > > - various cleanups, fixlets and code reorganization > > As usual, any sort of feedback, bugreport, fix and suggestion is more > than welcome, Load balancing appears to be badly broken in this version. When I started 4 hard spinners on my 2 CPU machine one ended up on one CPU and the other 3 on the other CPU and they stayed there. Peter -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/