From owner-freebsd-stable@FreeBSD.ORG Mon Sep 14 13:13:29 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CFB111065672 for ; Mon, 14 Sep 2009 13:13:29 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 9EB738FC13 for ; Mon, 14 Sep 2009 13:13:29 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 4FAC346B23; Mon, 14 Sep 2009 09:13:29 -0400 (EDT) Received: from jhbbsd.hudson-trading.com (unknown [209.249.190.8]) by bigwig.baldwin.cx (Postfix) with ESMTPA id 9B0DC8A01F; Mon, 14 Sep 2009 09:13:28 -0400 (EDT) From: John Baldwin To: freebsd-stable@freebsd.org Date: Mon, 14 Sep 2009 08:36:31 -0400 User-Agent: KMail/1.9.7 References: <4AA9A07C.4050200@pldrouin.net> <200909111105.01619.jhb@freebsd.org> <4AAA70C5.5090408@pldrouin.net> In-Reply-To: <4AAA70C5.5090408@pldrouin.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200909140836.31559.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Mon, 14 Sep 2009 09:13:28 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=4.2 tests=AWL,BAYES_00,RDNS_NONE autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: Pierre-Luc Drouin Subject: Re: How to enable CPU turbo mode on FreeBSD? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Sep 2009 13:13:29 -0000 On Friday 11 September 2009 11:46:13 am Pierre-Luc Drouin wrote: > John Baldwin wrote: > > On Thursday 10 September 2009 8:57:32 pm Pierre-Luc Drouin wrote: > > > >> Hi, > >> > >> I have an overclocked i7 920 CPU for which I have enabled Turbo Mode in > >> the BIOS (21x multiplier). The base clock is set at 190 MHz, so the CPU > >> frequency with Turbo mode activated should be 3990 MHz. However the > >> maximum value FreeBSD amd64 shows for the CPU frequency in dmesg and > >> sysctl is 3790 MHz. How can I enable the Turbo Mode? > >> > >> CPU: Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz (3790.52-MHz > >> K8-class CPU) > >> > >> machdep.acpi_timer_freq: 3579545 > >> machdep.tsc_freq: 3790522507 > >> machdep.i8254_freq: 1193182 > >> dev.cpu.0.freq: 349 > >> dev.cpu.0.freq_levels: 2793/130000 2443/113750 2094/97500 1745/81250 > >> 1396/65000 1047/48750 698/32500 349/16250 > >> > > > > You have to enable C2/C3 sleep states (possibly in your BIOS). However, > > FreeBD doesn't currently handle this but so well since that will probably > > turn off the local APIC timer interrupt when the CPU is idle causing FreeBSD > > to miss clock interrupts. > > > > > Sorry I am not sure exactly what you are referring to. Do you mean that > I need to enable C2/C3 states in order to have the correct max CPU freq > value displayed at boot time/in sysctl, or you mean that I need these > states in order to be able to use the Turbo Mode at all? Right now in > the BIOS I had the following features disabled to test the overclocking > (I was following what is recommended to do for Windows users to run > stress tests): > > -Intel SpeedStep: Use this function to enable the Intel SpeedStep > technology (EIST) > -CxE Function: This function allows you to select the lowest C state > supported according as CPU and MB. The options are Auto, Disabled, C1, > C1E, C3 and C6 You need to have C2/C3 enabled for it to work at all, at least on Nehalem processors. -- John Baldwin