From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261471AbVHBME7 (ORCPT ); Tue, 2 Aug 2005 08:04:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261469AbVHBME6 (ORCPT ); Tue, 2 Aug 2005 08:04:58 -0400 Received: from mail22.syd.optusnet.com.au ([211.29.133.160]:58816 "EHLO mail22.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S261463AbVHBME1 (ORCPT ); Tue, 2 Aug 2005 08:04:27 -0400 From: Con Kolivas To: Tony Lindgren Subject: Re: [patch] i386 dynamic ticks 2.6.13-rc4 (code reordered) Date: Tue, 2 Aug 2005 22:04:04 +1000 User-Agent: KMail/1.8.2 Cc: Lee Revell , linux-kernel@vger.kernel.org, tuukka.tikkanen@elektrobit.com, ck@vds.kolivas.org References: <200508021443.55429.kernel@kolivas.org> <200508022054.22276.kernel@kolivas.org> <20050802113137.GK15903@atomide.com> In-Reply-To: <20050802113137.GK15903@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200508022204.05562.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Aug 2005 21:31, Tony Lindgren wrote: > * Con Kolivas [050802 03:54]: > > > I need to ask you why you think limiting the maximum Hz is a bad idea? On > > a laptop, say we have set the powersave governor, we have already told > > the kernel we are interested in maximising power saving at the expense of > > performance. Would it not be appropriate for this to be linked in a way > > that sets maximum Hz to some value that maximises power save (whatever > > that value is) at that time? > > With dyntick the system will run at max HZ only when busy. It is possible > that cutting down max HZ might cause some savings while busy, but I would > assume the savings are minimal. > > I personally prefer to have the performance available when needed, and > max savings while idle. That's what I felt too but wasn't sure about the power saving. However what you say makes complete sense; if the machine is loaded then the extra power overhead of 1000 vs 100 ticks is meaningless, but throughput may be of concern. However I managed to get it booted on my p4 at home and while I'm using it under load I find it rarely gets to 1000Hz during realistic loads. I'll be posting a fresh patch shortly with the last few cleanups I could find, that I'm now running on 2.6.13-rc5. Cheers, Con