From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266666AbUBSHzX (ORCPT ); Thu, 19 Feb 2004 02:55:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266721AbUBSHzX (ORCPT ); Thu, 19 Feb 2004 02:55:23 -0500 Received: from av1-1-sn4.m-sp.skanova.net ([81.228.10.116]:54957 "EHLO av1-1-sn4.m-sp.skanova.net") by vger.kernel.org with ESMTP id S266666AbUBSHzN convert rfc822-to-8bit (ORCPT ); Thu, 19 Feb 2004 02:55:13 -0500 From: Roger Larsson To: Christoph Stueckjuergen , Robert Love Subject: Re: 2.6.1 Scheduler Latency Measurements (Preemption diabled/enabled) Date: Wed, 18 Feb 2004 22:00:04 +0100 User-Agent: KMail/1.6.51 Cc: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Message-Id: <200402182200.04754.roger.larsson@skelleftea.mail.telia.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Christoph Stueckjuergen wrote: >Hi, > >I performed a series of measurements comparing scheduler latency of a 2.6.1 >kernel with preemption enabled and disabled on an AMD Elan (i486 compatible) >with 133 Mhz clock frequency. OK, then you have worse hardware than I had when I started to measure latency :-) > - - - interesting way of trigger and measure deleted - - - > The results are: > "loaded" system, 10.000 samples > average scheduler latency (preemption enabled / disabled): 170 us / 232 us > minimum scheduler latency (preemption enabled / disabled): 49 us / 43 us > maximum scheduler latency (preemption enabled / disabled): 840 us / 1063 us > > "unloaded" system, 10.000 samples > average scheduler latency (preemption enabled / disabled): 50 us / 44 us > minimum scheduler latency (preemption enabled / disabled): 46 us / 41 us > maximum scheduler latency (preemption enabled / disabled): 233 us / 215 us > Robert Love said: > That said, I would of expected slightly better numbers. I would say that the numbers are quite good :-) For comparation check http://www.gardena.net/benno/linux/audio/ There are some load tests there that you can use to generate load: disk access, memory pressure, X11, ... Note that more memory can result in worse latency, longer linked lists to walk... /RogerL -- Roger Larsson Skellefteċ Sweden