From owner-freebsd-mobile@FreeBSD.ORG Sun Nov 2 22:06:24 2008 Return-Path: Delivered-To: freebsd-mobile@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B1BDA106564A; Sun, 2 Nov 2008 22:06:24 +0000 (UTC) (envelope-from mav@FreeBSD.org) Received: from cmail.optima.ua (cmail.optima.ua [195.248.191.121]) by mx1.freebsd.org (Postfix) with ESMTP id D3D508FC0C; Sun, 2 Nov 2008 22:06:23 +0000 (UTC) (envelope-from mav@FreeBSD.org) X-Spam-Flag: SKIP X-Spam-Yversion: Spamooborona-2.1.0 Received: from [212.86.226.226] (account mav@alkar.net HELO mavbook.mavhome.dp.ua) by cmail.optima.ua (CommuniGate Pro SMTP 5.2.9) with ESMTPSA id 226798405; Mon, 03 Nov 2008 00:06:22 +0200 Message-ID: <490E245C.7070900@FreeBSD.org> Date: Mon, 03 Nov 2008 00:06:20 +0200 From: Alexander Motin User-Agent: Thunderbird 2.0.0.17 (X11/20081029) MIME-Version: 1.0 To: "Alexandre \"Sunny\" Kovalenko" References: <490DF584.5080506@FreeBSD.org> <1225656933.1202.2.camel@RabbitsDen> In-Reply-To: <1225656933.1202.2.camel@RabbitsDen> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: FreeBSD acpi , freebsd-mobile@FreeBSD.org Subject: Re: Is the C3 possible with SMP? X-BeenThere: freebsd-mobile@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Mobile computing with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Nov 2008 22:06:24 -0000 Alexandre "Sunny" Kovalenko wrote: >> I have tried to enable C3 state on my Core2Duo laptop and found that it >> is not working good. System HZ timer stops during CPU sleep. After some >> investigation I have found that it is due to LAPIC timer used for HZ >> stopped during C3 state (same as during AMD's C1E). >> >> So the question is: Is it possible (or planned) to make it work somehow? >> For example, by using some external timer instead of LAPIC's one? >> >> ACPI reports about 20% less idle power consumption with C3 state >> comparing to C2. It would be interesting to get additional half an hour >> on battery. >> > You can get half way there by adding > > dev.cpu.1.cx_lowest=C3 > > to /etc/sysctl.conf Thanks. 1. Looks like it does not kill the timer. 2. I haven't got any benefit from it in idle state. According to `acpiconf -i 0` I have about 13 Amps (IMHO more looks like Watts) with both C2 and this half-to-C3, but only 11 Amps in full C3 (but without timer). 3. I have got about 10% benefit (33 Amps against 36) when cpu0 is 100% busy while cpu1 is idle. -- Alexander Motin