From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261573AbVGLOJV (ORCPT ); Tue, 12 Jul 2005 10:09:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261806AbVGLOJU (ORCPT ); Tue, 12 Jul 2005 10:09:20 -0400 Received: from linux01.gwdg.de ([134.76.13.21]:18395 "EHLO linux01.gwdg.de") by vger.kernel.org with ESMTP id S261573AbVGLOHE (ORCPT ); Tue, 12 Jul 2005 10:07:04 -0400 Date: Tue, 12 Jul 2005 16:05:16 +0200 (MEST) From: Jan Engelhardt To: Vojtech Pavlik cc: Con Kolivas , linux-kernel@vger.kernel.org, George Anzinger , "Martin J. Bligh" , Lee Revell , Diego Calleja , azarah@nosferatu.za.org, akpm@osdl.org, cw@f00f.org, torvalds@osdl.org, christoph@lameter.org Subject: Re: i386: Selectable Frequency of the Timer Interrupt In-Reply-To: <20050712133018.GA8467@ucw.cz> Message-ID: References: <200506231828.j5NISlCe020350@hera.kernel.org> <42D310ED.2000407@mvista.com> <20050712121008.GA7804@ucw.cz> <200507122239.03559.kernel@kolivas.org> <20050712133018.GA8467@ucw.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, >> > HZ ticks/jiffie 1 second error (ppm) >> > --------------------------------------------------- >> > 100 11932 1.000015238 15.2 I was not quite able to reproduce these values, probably because I got the math wrong. I used: $oneSecond = $ticksJiffie * $HZ / 1193182 which yields 11932*100/1193182 = 1.00001508571198693912, !=1.000015238 Math corrections welcome. Anyway, I've done some graphs. Intersting that the smaller the HZ, the less error (seen on a whole, esp. view_1k and view_8k.png) we get. 20Hz seems to be the 0.0 case, and 18Hz is not bad either. IIRC, DOS used 18HZ ;) http://jengelh.hopto.org/tick/ Jan Engelhardt -- | Alphagate Systems, http://alphagate.hopto.org/