From owner-freebsd-acpi@FreeBSD.ORG Mon Sep 10 13:43:11 2007 Return-Path: Delivered-To: freebsd-acpi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EFA6A16A419 for ; Mon, 10 Sep 2007 13:43:11 +0000 (UTC) (envelope-from william88@gmail.com) Received: from rv-out-0910.google.com (rv-out-0910.google.com [209.85.198.191]) by mx1.freebsd.org (Postfix) with ESMTP id A5BFF13C459 for ; Mon, 10 Sep 2007 13:43:11 +0000 (UTC) (envelope-from william88@gmail.com) Received: by rv-out-0910.google.com with SMTP id l15so989983rvb for ; Mon, 10 Sep 2007 06:43:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; bh=t4Y+kLc7RejpKF63Qo5AIwW3RWv7u5oFtCH+Ye+QR6c=; b=Frh6FjebzARrg99fGGFbjollPm4TDjQM+mnq56+feIzeQdWMTJoLl2Ki8QDeGJn4+FvtioS0nuSaudOTXWrliPGMEGFvUTwwEBgsQw8skUF7ISDmLM7HKW8FZVGCpFeZswlVaCFlgTSLzhsvkuVvQrFkUXRw0fVI5WhpvIQMNiE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=ePxUGjDg9v9d7S+0YvaRs6+/Lntv4gP3sKN5GPseomdAiTFo4FMoWg2nB2e3POysBeypYUW1Pmws4YRnb1WOa1jcfWFFKisnsxI5GuJTQP1nHvR4AMAaxydzXiEQLFilBHaQd9ManxfncrHOzJlqW/vIx8jLJLEF6hr/pOj8Slw= Received: by 10.141.167.5 with SMTP id u5mr972812rvo.1189431791128; Mon, 10 Sep 2007 06:43:11 -0700 (PDT) Received: by 10.141.136.13 with HTTP; Mon, 10 Sep 2007 06:43:11 -0700 (PDT) Message-ID: <632825b40709100643t40c41376xc69e7096d637fa8c@mail.gmail.com> Date: Mon, 10 Sep 2007 10:43:11 -0300 From: "William Grzybowski" To: "Kevin Oberman" In-Reply-To: <20070907213724.F1D384500E@ptavv.es.net> MIME-Version: 1.0 References: <20070907213724.F1D384500E@ptavv.es.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-acpi@freebsd.org Subject: Re: powerd algorithms X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 10 Sep 2007 13:43:12 -0000 On 9/7/07, Kevin Oberman wrote: > > > Date: Fri, 7 Sep 2007 22:14:53 +0200 > > From: "Cyrille Szymanski" > > Sender: owner-freebsd-acpi@freebsd.org > > > > > Hi Cyrille, > > > > > > Would be nice if you can share you research about powerd with me, i am > really interested in this subject... > > > > My biggest concerns (and why I more or less lost interest in this > > project) are that : > > 1. I believe FLAT to be very close to, if not the best universal > > algorithm possible; > > 2. I was unable to find a decent way to quantify the power savings of > > each approach other than by simulation or using current probes. > > > > Power consumption depends both on frequency and workload and since I > > have no idea how CPUs behave in practice I cannot design any smarter > > solution. The best solution is likely to be something specific to each > > CPU model/brand (see bullet 1). This would require building a database > > of the optimum settings for each CPU model. I am not sure we find > > enough people willing to experiment, unless... (see bullet 2). > > > > Note: I am not convinced that my laptop uses less power when running > > at its lowest frequency when I see the heat that it emits in that > > mode. > > > > > Actually the powerd has 3 modes right? [min,max,adaptive] > > > The adaptive uses the relation about idle and total usage, but just > one by one, i was thinking in use a short historical of this cpu usage > related by idle and create some profiles over it (like ondemand and > conservative in linux)... > > > > AFAIK the 'adaptive' mode increases by two steps and decreases by one > > step (this would be more responsive). If you look at CVS revisions for > > powerd.c you'll see what has been tried over the years (rev 1.9 for > > example) > http://www.freebsd.org/cgi/cvsweb.cgi/src/usr.sbin/powerd/powerd.c > > > > Have you checked the research papers describing approaches such as > > PAST, FLAT etc. ? I did not investigate the linux 'ondemand' and I have to take a look in ondemand code, but i always worked fine to me, maybe it really worth a try as you said. > 'conservative' modes but maybe they are worth a try. As I understand > > it, FreeBSD lacks only the 'ondemand' mode ? Not completely, but I will take a look. Cyrille, > > Three ago I did some analysis of the effects of power management on some > laptops of that era. Most had either no voltage-frequency management or > only the basic SST...not EST. I really should do some current testing. I > still think I have all of the scripts I used to do this, but all testing > was done at 100% CPU utilization or idle. > > I found that simple CPU throttling was not too effective as a power > management tool. Not totally ineffective, but not very good. SpeedStep > was effective. I suspect EST with both voltage and frequency control > would be much better as would the AMD and maybe VIA equivalents. > > I was planning on modifying my tests to report at various levels of CPU > utilization, but then got tied up on other things and have not gotten > back to it. I did determine that running at 800 MHz frequency (SST) with > the CPU loaded at 90% used quite a bit more power than running at 1.2 > GHZ at 60%. I would be happy to provide my perl scripts to someone who > would like to expand them to test at other than 100% and 0% load. > Hi Kevin, You can send this scripts to me, thanks. As I can understand you are saying throttling is not that effective about power consuming, but I guess this is not the unique point to discuss. Tell me if i got i wrong ;) Better than this is just use low frequencies when you don't need higher process power and with it, take down the >cpu temperature< and less use of the cooler... Bye. -- William Grzybowski ------------------------------------------ Jabber: william88 at gmail dot com Curitiba/PR - Brazil