From owner-cvs-src@FreeBSD.ORG Tue Aug 30 08:53:06 2005 Return-Path: X-Original-To: cvs-src@freebsd.org Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 16FFE16A41F; Tue, 30 Aug 2005 08:53:06 +0000 (GMT) (envelope-from bruno@poupinou.org) Received: from poup.poupinou.org (poup.poupinou.org [195.101.94.96]) by mx1.FreeBSD.org (Postfix) with ESMTP id A974C43D45; Tue, 30 Aug 2005 08:53:05 +0000 (GMT) (envelope-from bruno@poupinou.org) Received: from bruno by poup.poupinou.org with local (Exim) id 1EA1r5-0000qW-00; Tue, 30 Aug 2005 10:52:31 +0200 Date: Tue, 30 Aug 2005 10:52:31 +0200 To: Nate Lawson Message-ID: <20050830085231.GA31034@poupinou.org> References: <200508240752.j7O7qxep016309@repoman.freebsd.org> <43129EE6.7040608@root.org> <20050829073821.GI7749@poupinou.org> <4313E9C9.5050508@root.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4313E9C9.5050508@root.org> User-Agent: Mutt/1.5.9i From: Bruno Ducrot Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, Hajimu UMEMOTO , cvs-all@FreeBSD.org Subject: Re: cvs commit: src/usr.sbin/powerd powerd.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Aug 2005 08:53:06 -0000 On Mon, Aug 29, 2005 at 10:08:25PM -0700, Nate Lawson wrote: > Bruno Ducrot wrote: > >On Sun, Aug 28, 2005 at 10:36:38PM -0700, Nate Lawson wrote: > > > >>Another mitigating factor is a patch I hope to commit soon that removes > >>levels that aren't useful. The general idea is the same as a recent > >>email from Tijl Coosemans but my approach is different. > > > > > >I'm pretty sure it's incorrect to add p4tcc and acpi_throttle for power > >saving purpose. I plan to add some flags in order to use only relevant > >frequencies to this end, but IMHO that should be done at low-level > >drivers. On the other hand, it is usefull to keep the existing sysctl > >freqs, but for cooling purpose only. > > I think throttling, whether via p4tcc or acpi_throttle, is a useful > addition to absolute frequency control (i.e. est or powernow). With > appropriate tuning, as I hope the patch I committed provides, the > additional levels should be helpful. Apart on older processors, I don't see the usefullness for power saving purpose. The problem is that when the processor is in stop grant state in the duty cycle, it will consume more power than when it is in sleep or deep sleep states (or deeper sleep state for some). If the processor is idle, you will have nearly like 100% of time spend in sleep state (for laptops) or stop grant state (for desktop), or even better if the system support C3 etc. But if you have a duty cycle of (say) 87.5% due to the idleness of the system (and the result of powerd), then the processor will be put for 87.5% of time in stop grant state which consume more power than sleep state. -- Bruno Ducrot -- Which is worse: ignorance or apathy? -- Don't know. Don't care.