From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fred Blaise Subject: Re: battery life with cpufreq Date: Mon, 19 Sep 2005 11:35:24 +0200 Message-ID: <9cfa150205091902354d5b4c43@mail.gmail.com> References: <9cfa150205091902116057595e@mail.gmail.com> <20050919092448.GA9023@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: <20050919092448.GA9023-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 , Fred Blaise , acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-acpi@vger.kernel.org On 9/19/05, Dominik Brodowski wrote: > Hi, >=20 > On Mon, Sep 19, 2005 at 11:11:01AM +0200, Fred Blaise wrote: > > I have an dell inspiron 5150, 3Ghz. I have loaded p4_clockmod, and my > > CPU frequency now changes with powernowd. It seems to work well. > > > > However, I am not seeing any battery life improvement. > > > > Any ideas? >=20 > Yes. In general, throttling doesn't improve battery life, only CPU freque= ncy > scaling does: ok.. So the fact that my CPU goes down to 383Mghz instead of the normal 3Ghz is not frequency scaling? (pardon the noob that I am if this question doesn't make sense) >=20 > "In contrast to CPU frequency scaling, where the operating frequency is > constantly modulated, throttling means the CPU is forced to a halt for sh= ort > periods of time. If throttled, the CPU [enters] into a physical and > electrical state comparable to the idling states mentioned above, so it c= an > be described as an enforced idling of the CPU. >=20 > As certain CPU power state typically utilize similar hardware > implementations, and as throttling does not have a positive effect on the > energy consumption during CPU power states, throttling the CPU by a given > rate is only useful if the CPU is less idle than the throttling rate." >=20 > Dominik > ------------------------------------------------------- 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