From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261887AbVGJKp2 (ORCPT ); Sun, 10 Jul 2005 06:45:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261888AbVGJKp2 (ORCPT ); Sun, 10 Jul 2005 06:45:28 -0400 Received: from 167.imtp.Ilyichevsk.Odessa.UA ([195.66.192.167]:10384 "HELO port.imtp.ilyichevsk.odessa.ua") by vger.kernel.org with SMTP id S261887AbVGJKp0 (ORCPT ); Sun, 10 Jul 2005 06:45:26 -0400 From: Denis Vlasenko To: Linus Torvalds , Andrew Morton Subject: Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt Date: Sun, 10 Jul 2005 13:45:13 +0300 User-Agent: KMail/1.5.4 Cc: Chris Wedgwood , linux-kernel@vger.kernel.org, christoph@lameter.org References: <200506231828.j5NISlCe020350@hera.kernel.org> <20050708145953.0b2d8030.akpm@osdl.org> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="koi8-r" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200507101345.13291.vda@ilport.com.ua> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 09 July 2005 01:08, Linus Torvalds wrote: > > On Fri, 8 Jul 2005, Andrew Morton wrote: > > > > > > The previous value here i386 is 1000 --- so why is the default 250. > > > > Because 1000 is too high. > > Yes. I chose 1000 originally partly as a way to make sure that people that > assumed HZ was 100 would get a swift kick in the pants. That meant making > a _big_ change, not a small subtle one. For example, people tend to react > if "uptime" suddenly says the machine has been up for a hundred days (even > if it's really only been up for ten), but if it is off by just a factor of > two, it might be overlooked. > > So 1kHz was a bit of an overkill, but it worked well enough that we never > really got around to changing it. There are lots of HZ/100 in the kernel. With either 100 or 1000 it divides exactly, but with 250 it's wrong by 20%. -- vda