From owner-freebsd-questions@FreeBSD.ORG Wed Jan 28 06:33:26 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9E6AE106564A for ; Wed, 28 Jan 2009 06:33:26 +0000 (UTC) (envelope-from shawnbadger@gmail.com) Received: from wf-out-1314.google.com (wf-out-1314.google.com [209.85.200.175]) by mx1.freebsd.org (Postfix) with ESMTP id 6D9148FC0A for ; Wed, 28 Jan 2009 06:33:26 +0000 (UTC) (envelope-from shawnbadger@gmail.com) Received: by wf-out-1314.google.com with SMTP id 24so7272165wfg.7 for ; Tue, 27 Jan 2009 22:33:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from :user-agent:mime-version:to:cc:subject:references:in-reply-to :content-type:content-transfer-encoding; bh=XWKZKFsZ66LqpUtPsush8VG6OfJaJMorFz2ormL8uRU=; b=jsbWeeqszYEV73T8x628mY8zbhMlVEGhqYtf2w16iSzPBxiOnAcKb4o1EDErVnn7sx CWstsGVZLhH/9A5VcdlEZBL3Gm3/KijJMdHbce58oyX85b9b99n6i4oY0CH6VtYT632P FTEU9Cc60h/rfX7WZzUokm8tVshmGy7C3nN40= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=Xxf/Wg6QbhV9hi6VEpCFHzqYwfDv4XBHiViij4JM3KLB2zsAX8XBkLRxHAPwkvBLAJ 6yRxtcT3Ub0ou+4hV3mqWw4hEb7eInLJLnNOO5hofre6gcSppOahdt/hJzqfMwEBgLv3 J2BbigeozhQcFxpgVlb2N9JAAVMexSNfc31VY= Received: by 10.142.194.1 with SMTP id r1mr290517wff.21.1233124405760; Tue, 27 Jan 2009 22:33:25 -0800 (PST) Received: from ?192.168.1.132? (69.169.154.48.provo.static.broadweave.net [69.169.154.48]) by mx.google.com with ESMTPS id 22sm34802636wfi.58.2009.01.27.22.33.24 (version=TLSv1/SSLv3 cipher=RC4-MD5); Tue, 27 Jan 2009 22:33:25 -0800 (PST) Message-ID: <497FFBEA.1040102@gmail.com> Date: Tue, 27 Jan 2009 23:32:10 -0700 From: Shawn Badger User-Agent: Thunderbird 2.0.0.18 (X11/20081205) To: Bruce Cran References: <497F9683.3080905@gmail.com> <20090128060956.0c164685@gluon> In-Reply-To: <20090128060956.0c164685@gluon> Content-Transfer-Encoding: 7bit MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-questions@freebsd.org Subject: Re: Laptop battery life on FreeBSD X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Jan 2009 06:33:26 -0000 Bruce Cran wrote: On Tue, 27 Jan 2009 16:19:31 -0700 Shawn Badger [1] wrote: Hi, I recently installed FreeBSD 7.1 on my laptop, replacing Arch Linux and I noticed a significant drop in my battery life (from ~3 hours to ~1.5 hours). I realize that Linux has their "tickless" kernel, which I am sure explains the difference, but my question is... is there anything I can do in FreeBSD right now to improve this? And is there going to be any work done the kernel to allow the hardware to enter into a low-power state for an extended period of time? My laptop is an Acer Travelmate 4100 which has the following hardware: - Pentium M 1.6 GHz processer - 2 GB RAM - integrated video/sound - 802.11bg / bluetooth I'm somewhat of a minimalist and don't use X11. I've disabled the bluetooth adapter, but frequently use my wireless adapter (intel pro/2200bg). Does anyone have any suggestions that could potentially extend my battery life? powerd isn't run by default, so the laptop will always be running at maximum frequency. By putting powerd_enable="YES" in /etc/rc.conf the CPU will throttle back whenever the system is idle. You can also tell FreeBSD to enter lower Cx states when idle by setting dev.cpu.x.cx_lowest, if it's supported. For example my VIA EPIA system has the following dev.cpu tree: sysctl dev.cpu dev.cpu.0.%desc: ACPI CPU dev.cpu.0.%driver: cpu dev.cpu.0.%location: handle=\_PR_.CPU0 dev.cpu.0.%pnpinfo: _HID=none _UID=0 dev.cpu.0.%parent: acpi0 dev.cpu.0.freq: 533 dev.cpu.0.freq_levels: 533/-1 266/-1 dev.cpu.0.cx_supported: C1/0 C2/90 C3/900 dev.cpu.0.cx_lowest: C1 dev.cpu.0.cx_usage: 100.00% 0.00% 0.00% My processor now throttles down to 100 MHz when idle and my fan no longer blows like crazy - this is exactly what I was hoping for. Thanks, Shawn References 1. mailto:shawnbadger@gmail.com