From owner-freebsd-questions@FreeBSD.ORG Thu Feb 1 21:42:11 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id B140816A405 for ; Thu, 1 Feb 2007 21:42:11 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from mxout5.cac.washington.edu (mxout5.cac.washington.edu [140.142.32.135]) by mx1.freebsd.org (Postfix) with ESMTP id 9602E13C461 for ; Thu, 1 Feb 2007 21:42:11 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from hymn05.u.washington.edu (hymn05.u.washington.edu [140.142.12.184]) by mxout5.cac.washington.edu (8.13.7+UW06.06/8.13.7+UW06.09) with ESMTP id l11LgAcM008592 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 1 Feb 2007 13:42:11 -0800 Received: from localhost (localhost [127.0.0.1]) by hymn05.u.washington.edu (8.13.7+UW06.06/8.13.7+UW06.09) with ESMTP id l11LgAdk028084 for ; Thu, 1 Feb 2007 13:42:10 -0800 X-Auth-Received: from [192.55.52.1] by hymn05.u.washington.edu via HTTP; Thu, 01 Feb 2007 13:42:10 PST Date: Thu, 1 Feb 2007 13:42:10 -0800 (PST) From: youshi10@u.washington.edu To: freebsd-questions@freebsd.org In-Reply-To: <45C245AE.6020308@wcborstel.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-PMX-Version: 5.3.0.289146, Antispam-Engine: 2.5.0.283055, Antispam-Data: 2007.2.1.132933 X-Uwash-Spam: Gauge=IIIIIII, Probability=7%, Report='NO_REAL_NAME 0, __CP_URI_IN_BODY 0, __CT 0, __CT_TEXT_PLAIN 0, __HAS_MSGID 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __SANE_MSGID 0' Subject: Re: gcc compiler cputype, prescott or nocona confusion 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: Thu, 01 Feb 2007 21:42:11 -0000 On Thu, 1 Feb 2007, Jorn Argelo wrote: > Garrett Cooper wrote: >> Jorn Argelo wrote: >>> >>> On Wed, 31 Jan 2007 23:40:38 +1100, Scott Killen >>> wrote: >>>> Hi, >>>> >>>> When recompiling the world or kernel in FreeBSD i386 Rel 6.1 with, >>>> >>>> "# make buildworld" >>>> or >>>> "# make buildkernel KERNCONF=MYSMPCONF" >>>> >>>> (or building anything anything else for that matter), even though I have >>>> "CPUTYPE?=nocona" set in my "/etc/make.conf" file the compiler seems to >>>> head >>>> back to a default of "-march=prescott" when compiling many of the >>>> functions >>>> on a Dual Xeon 3.6g (nocona) machine! >>>> >>>> This doesn't happen when compiling for other machine types, I've tried >>>> it >>>> on a >>>> Dual PentiumPro, Dual PII, Dual PIII setting the CPUTYPE to the correct >>>> cpu >>>> type and the -march sticks to the assigned cpu type through all >>>> operations >>>> and produces nice quick optimized code. >>>> >>>> Why is this so? >>>> >>>> Is it because the "nocona" machine type optimization refers to the EMT64 >>>> technology and thus is rejected when compiling for i386 targets rather >>>> than >>>> amd64 or emt64 targets and Gcc rejects it? >>> >>> That's right. AFAIK the Nocona core is a prescott with EM64T support (feel >>> free to correct me if I am wrong). Basically you have an i386 version of >>> FreeBSD, and with EM64T instructions enabled GCC will build a 64-bit >>> version of FreeBSD. I think that's the reason it switches back to >>> prescott. >> >> Most of the time you're right. However (for starters), some nocona chips >> feature 2MB cache instead of 1MB cache: >> >> . >> >> I'd have to look more in depth, but OTOH the nocona also featured some >> architecture upgrades, other than just the "64-bit'ness" >> >> I heard that gcc 3.4.x was pretty funky with the nocona processors though, >> and prescott's a more stable target; that changed a bit in gcc 4.x I think. >> Or maybe I'm just mixing up nocona and yonah in this case. >> -Garrett > > Yonah is the Pentium M version of the first Core generation I believe. Or maybe > it was still a Netburst, I can't remember. > > Jorn Yonah is the first version of the Core Duo generation processors. -Garrett