From owner-freebsd-current@FreeBSD.ORG Tue Jan 6 07:56:17 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 52D0A16A4CE for ; Tue, 6 Jan 2004 07:56:17 -0800 (PST) Received: from mail4.speakeasy.net (mail4.speakeasy.net [216.254.0.204]) by mx1.FreeBSD.org (Postfix) with ESMTP id E606843D1F for ; Tue, 6 Jan 2004 07:56:15 -0800 (PST) (envelope-from jhb@FreeBSD.org) Received: (qmail 3121 invoked from network); 6 Jan 2004 15:56:15 -0000 Received: from dsl027-160-063.atl1.dsl.speakeasy.net (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) encrypted SMTP for ; 6 Jan 2004 15:56:15 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.12.10/8.12.10) with ESMTP id i06FuBM0025704; Tue, 6 Jan 2004 10:56:12 -0500 (EST) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.4 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <200401061630.41005@harrymail> Date: Tue, 06 Jan 2004 10:56:20 -0500 (EST) From: John Baldwin To: Harald Schmalzbauer X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) cc: freebsd-current@FreeBSD.org Subject: Re: some HTT questions X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Jan 2004 15:56:17 -0000 On 06-Jan-2004 Harald Schmalzbauer wrote: > On Tuesday 06 January 2004 16:21, John Baldwin wrote: >> On 06-Jan-2004 Harald Schmalzbauer wrote: >> > Hi all, >> > >> > I'm currently working on my first P4 ever. >> > I'm planning a colo production machine with FreeBSD 5.2 (RC2 atm). >> > The info of dmesg about the CPU shows: >> > >> > CPU: Intel(R) Pentium(R) 4 CPU 2.40GHz (2394.13-MHz 686-class CPU) >> > Origin = "GenuineIntel" Id = 0xf27 Stepping = 7 >> > >> > Features=0xbfebfbff> >MCA,CMOV,PAT,PSE36,CLFLUS H,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> >> > >> > So I think this CPU should be HyperThreading capable which gets hardened >> > by those lines: >> > >> > acpi_cpu0: on acpi0 >> > acpi_cpu1: on acpi0 >> > >> > But the next line gives my an error about CPU1: >> > >> > device_probe_and_attach: acpi_cpu1 attach returned 6 >> > >> > This line shows up a second time between probing of sio and nxp0. >> > >> > Ny my guess was that HTT should be enabled in the BIOS but the BIOS has >> > no entry about HTT. >> > >> > How can I use HTT and are my assumptions correct? >> >> Your assumptions are not correct. :) If your CPU does support HTT, then >> the dmesg will include an extra line that says >> ' Hyperthreading: X logical cpus'. The HTT Feature just means that we >> can check to see if this CPU has more than one core. It might still > > The Feature= doesn't mean it supports HTT but means we are allowed to > check if it supports HyperThreading??? Well that's total control. Yes, the feature bit just means that it supports the registers that list the number of CPUs. When we look at that register, it then says it has one logical CPU, effectively no HTT. :) -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/