From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753507AbXDPVGJ (ORCPT ); Mon, 16 Apr 2007 17:06:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753072AbXDPVGJ (ORCPT ); Mon, 16 Apr 2007 17:06:09 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:37756 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753507AbXDPVGI (ORCPT ); Mon, 16 Apr 2007 17:06:08 -0400 Date: Mon, 16 Apr 2007 23:05:56 +0200 From: Ingo Molnar To: Andi Kleen Cc: linux-kernel@vger.kernel.org Subject: Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS] Message-ID: <20070416210556.GA25637@elte.hu> References: <20070413202100.GA9957@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7 -2.0 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 * Andi Kleen wrote: > > i'm pleased to announce the first release of the "Modular Scheduler > > Core and Completely Fair Scheduler [CFS]" patchset: > > > > http://redhat.com/~mingo/cfs-scheduler/sched-modular+cfs.patch > > I would suggest to drop the tsc.c change. The "small errors" can be > really large on some systems and you can also see large backward > jumps. actually, i designed the CFS code assuming a per-CPU TSC (with no global synchronization), not assuming any globally sync TSC. In fact i wrote it on such systems: a CoreDuo2 box that has stops the TSC in C3 and the different cores have wildly different TSC values and a dual-core Athlon64 that quickly drifts its TSC. So i'll keep the sched_clock() change for now. > BTW with all this CPU time measurement it would be really nice to > report it to the user too. It seems a bit bizarre that the scheduler > keeps track of ns, but top only knows jiffies with large sampling > errors. yeah - i'll fix that too if someone doesnt beat me at it. Ingo