From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262177AbULMASw (ORCPT ); Sun, 12 Dec 2004 19:18:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262179AbULMASw (ORCPT ); Sun, 12 Dec 2004 19:18:52 -0500 Received: from mail22.syd.optusnet.com.au ([211.29.133.160]:29836 "EHLO mail22.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S262177AbULMASg (ORCPT ); Sun, 12 Dec 2004 19:18:36 -0500 References: <20041211142317.GF16322@dualathlon.random> <20041212163547.GB6286@elf.ucw.cz> <20041212222312.GN16322@dualathlon.random> <41BCD5F3.80401@kolivas.org> <20041212234331.GO16322@dualathlon.random> Message-ID: X-Mailer: http://www.courier-mta.org/cone/ From: Con Kolivas To: Andrea Arcangeli Cc: Con Kolivas , Pavel Machek , linux-kernel@vger.kernel.org Subject: Re: dynamic-hz Date: Mon, 13 Dec 2004 11:18:15 +1100 Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset="US-ASCII" Content-Disposition: inline Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrea Arcangeli writes: > On Mon, Dec 13, 2004 at 10:36:19AM +1100, Con Kolivas wrote: >> The performance benefit, if any, is often lost in noise during >> benchmarks and when there, is less than 1%. So I was wondering if you >> had some specific advantage in mind for this patch? Is there some >> arch-specific advantage? I can certainly envision disadvantages to lower Hz. > > My last number I've here is 1% for kernel compile. We're not talking > fancy desktop stuff here, we're talking about raw computing servers that > runs in userspace 99.9% of the time where the 1% loss is going to be > multiplied dozen or hundred of times. For those HZ=1000 is a pure > tangible disavantage. > > For desktops 1% of cpu being lost is not an issue of course. Thanks. I have to admit that the real reason I wrote this email was for this discussion to go on record so that desktop users would not get inappropriately excited by this change. Cheers, Con