From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262284AbULMTnu (ORCPT ); Mon, 13 Dec 2004 14:43:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262283AbULMTlQ (ORCPT ); Mon, 13 Dec 2004 14:41:16 -0500 Received: from gprs215-167.eurotel.cz ([160.218.215.167]:3968 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S262286AbULMTEr (ORCPT ); Mon, 13 Dec 2004 14:04:47 -0500 Date: Mon, 13 Dec 2004 20:04:14 +0100 From: Pavel Machek To: Alan Cox , Stefan Seyfried , Con Kolivas , Linux Kernel Mailing List , Andrea Arcangeli Subject: Re: dynamic-hz Message-ID: <20041213190414.GA1052@elf.ucw.cz> References: <20041211142317.GF16322@dualathlon.random> <20041212163547.GB6286@elf.ucw.cz> <20041212222312.GN16322@dualathlon.random> <41BCD5F3.80401@kolivas.org> <41BD483B.1000704@suse.de> <20041213135820.A24748@flint.arm.linux.org.uk> <1102949565.2687.2.camel@localhost.localdomain> <20041213162355.E24748@flint.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041213162355.E24748@flint.arm.linux.org.uk> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > Lets take an example. Lets say that: > > > * a CPU runs at about 245mA when active > > > * 90mA when inactive > > > * the timer interrupt takes 2us to execute 1000 times a second > > > * no other processing is occuring > > > > Now take a real laptop and the numbers are in the 20W (15A) range. > > Roughly 650mA for my laptop while idle or just under 7W - by calculation > from battery capacity and measured lifetime. The question is how much > of that is due to the CPU itself and how much is due to the > peripherals. On Arima notebook here, whole machine takes 28W on 800MHz, idle (measured using external power meter), 33W with max backlight, and 68W at 2GHz, computing. Going to HZ=100 makes it one Watt less. I'd say that's quite significant. [17W number was based on internal power meter when running on battery]. So yes, CPU *is* taking more than all other perihepals. Pavel -- People were complaining that M$ turns users into beta-testers... ...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!