From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bas Mevissen Subject: Re: Pentium-M (Centrino): no power saved? Date: Tue, 23 Sep 2003 10:51:01 +0200 Sender: cpufreq-bounces@www.linux.org.uk Message-ID: <3F700975.9090402@basmevissen.nl> References: <3F6ACB0E.8050009@basmevissen.nl> <3F6EAC05.7090009@basmevissen.nl> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: cpufreq-bounces@www.linux.org.uk Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Jan Rychter Cc: cpufreq@www.linux.org.uk Jan Rychter wrote: >>>>>>>>"Bas" == Bas Mevissen writes: >> >> >>Do you measure this from the ACPI battery output? > > Yes. > OK. Do you know of a way to see the power usage when on AC-adapter? I'm wondering if there isn't something in the on-board power circuit to see the actual power usage of the PC or just CPU or motherboard. > No, I have verified this (with bogomips) and the above results are > true. The CPU does indeed slow down properly as directed by > cpufreq. Also, in my case connecting and disconnecting the AC adapter > doesn't change the CPU speed. > > So, the results still hold -- and it seems it simply doesn't make much > sense to slow down a Pentium-M, unless you really keep the CPU busy? > Very interesting conclusion. It could mean three things: 1) The internal power management of the Pentium-M (when using APM or ACPI idle calls) is very good 2) The speedstepping of the Pentium-M doesn't bring enough 3) We are interpreting something wrong :-) From your conclusions, 1) would be the most reasonable and most favourable result. Bas.