From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rutger Nijlunsing Subject: Re: cpufreq and p4 prescott Date: Sun, 16 May 2004 15:20:20 +0200 Sender: cpufreq-bounces@www.linux.org.uk Message-ID: <20040516132020.GA14608@nospam.com> References: <20040513173946.GA8238@dominikbrodowski.de> <20040514214751.GA8433@nospam.com> <20040515064434.GB8572@dominikbrodowski.de> <20040515105200.GA8095@nospam.com> <20040515194124.GA8212@dominikbrodowski.de> Reply-To: linux-kernel@tux.tmfweb.nl Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20040515194124.GA8212@dominikbrodowski.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: cpufreq-bounces+glkc-cpufreq=gmane.org@www.linux.org.uk Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: cpufreq@www.linux.org.uk, linux-kernel@vger.kernel.org, moqua@kurtenba.ch > > The only thing I could find in Intel's documentation is the max. time > > of throttling is 3 microseconds (p.67; 5.2.1 of Prescott > > datasheet). So this 3 microseconds should correspond to 5600 ticks or > > so... > > Can't find it in the datasheets right now, but did find an interesting > comment in section 13.15.3 of 24547212.pdf which explains the strange > behaviour we're seeing. Hm, 13.16.3 in my version, but indeed: all logical processors should be put asleep in the same way ;) > > > I know this is not P4 specific, but motherboard specific, but do > > you know of modules which use motherboard specific knowledge to scale > > the processor? > No. > > If the BIOS can do it, so should we be able to do it. > > Dynamic frequency scaling is (probably) way different from setting a > frequency at boot (which is what the BIOS does). Timing issues, settling > times, etc. are way too complicated, AFAICS. Even trying to do this might > result in severe non-recoverable hardware failures. Probably true for some motherboards, but Asus got a WinXP program called 'AiBooster' which is a program to under/overclock from -50% to +33% runtime (butt-ugly UI can be seen in http://www.asuscom.de/pub/ASUS/mb/sock478/p4p800/AIBooster_u.pdf). Could Wine be used (given the right permissions) to run or disect such a utility to make underclocking reality under Linux? *hopeful* Or has Asus released the specification of its motherboard? -- Rutger Nijlunsing ---------------------------- rutger ed tux tmfweb nl never attribute to a conspiracy which can be explained by incompetence ----------------------------------------------------------------------