From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Rychter Subject: Re: [PATCHSET] 0/3 Dynamic cpufreq governor and updates to ACPI P-state driver Date: Sun, 02 Nov 2003 12:28:44 -0800 Sender: cpufreq-bounces@www.linux.org.uk Message-ID: References: <88056F38E9E48644A0F562A38C64FB6007793C@scsmsx403.sc.intel.com> Mime-Version: 1.0 Return-path: In-Reply-To: <88056F38E9E48644A0F562A38C64FB6007793C@scsmsx403.sc.intel.com> (Venkatesh Pallipadi's message of "Wed, 22 Oct 2003 11:21:22 -0700") 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" Content-Transfer-Encoding: 7bit To: "Pallipadi, Venkatesh" Cc: Mukesh Rajan , linux-acpilinux-acpi@intel.com, cpufreq@www.linux.org.uk >>>>> "Venkatesh" == Venkatesh Pallipadi writes: Venkatesh> I do not have any performance numbers taken from actual Venkatesh> probes. We have seen in our testing that the the frequency Venkatesh> does change based on the cpu usage. For example, on a Venkatesh> Centrino system, Venkatesh> - frequency will be lowest when system is idle Venkatesh> - frequency will be somewhere in the mid-range when you run Venkatesh> single app like mp3/mpeg player Venkatesh> - frequency will be maximum when you run multiple apps Venkatesh> And with the kind of power savings that comes with these Venkatesh> frequency changes, this behaviour results in longer battery Venkatesh> life. However, as yet I do not have any numbers to quantify Venkatesh> this gain, mainly because I do not have any setup where I Venkatesh> can measure actual power. [...] Interesting. I have done some measurements on a Toshiba S7/290LNKW, which has a 900MHz Pentium-M. The results have been posted to this list a while ago -- the most surprising one being that the Pentium-M in that machine seemed to always consume the same amount of power when idle, independent of operating frequency. The frequency only made a difference when the CPU was actually doing something (or when I made it not use the C3 state by loading usb-uhci). Another interesting result was that in general, my P-III based laptop has lower power consumption than the Centrino-based one. Runs against the Centrino advertising campaign. My measurements were done using the ACPI battery status and overall seemed to make a lot of sense, except for this little detail. Can anybody from Intel confirm that this is the way it is supposed to be? --J.