From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fred Blaise Subject: Re: battery life with cpufreq Date: Mon, 19 Sep 2005 13:39:49 +0200 Message-ID: <9cfa150205091904396e66c2ea@mail.gmail.com> References: <9cfa150205091902116057595e@mail.gmail.com> <20050919092448.GA9023@isilmar.linta.de> <9cfa150205091902354d5b4c43@mail.gmail.com> <1127123139.11913.2.camel@nouse.net> <20050919094827.GB26933@isilmar.linta.de> <9cfa1502050919025331a15ad0@mail.gmail.com> <20050919095715.GA29988@isilmar.linta.de> <20050919101808.GA2411@tangens.sinus.cz> <20050919102251.GB13041@isilmar.linta.de> Reply-To: chapeaurouge-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20050919102251.GB13041-JwFqNg2GrOVrgjWwlLH9qw@public.gmane.org> Content-Disposition: inline Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Dominik Brodowski , Pavel Troller , Fred Blaise , Timo Hoenig , acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-acpi@vger.kernel.org On 9/19/05, Dominik Brodowski wrote: > > Hi, > > ok, it's clear. But isn't it true that in the periods with clock stop= ped > > the CPU consumes much less power than in those with clock running ? >=20 > Yes, indeed. However, it consumes exactly the same amount of energy as if= it > were in an "idle state" (ACPI C-States). And that's entered automatically= if > there is nothing for the CPU to do. As a typical CPU in a typical noteboo= k > only has something to do for 5% of the time, throttling to 75%, for examp= le, > means the CPU is: > working 5% > idling 20% > throttling 75% >=20 > moving "time" around from idling to throttling or the other way around > doesn't matter anything. If you use CPU frequency scaling, though, the > "working" part consumes less CPU power. Also, the "idle state" typically > consumes less power if the CPU frequency and voltage was scaled down. To sum up, I am screwed I guess :\ Since the speedstep* don't work for me... No long battery life for me... Thanks for your explanations. >=20 > Dominik fred > ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php