From owner-freebsd-questions@FreeBSD.ORG Wed Jan 31 16:24:59 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 7B95216A402 for ; Wed, 31 Jan 2007 16:24:59 +0000 (UTC) (envelope-from jorn@wcborstel.com) Received: from mail.wcborstel.com (wcborstel.xs4all.nl [82.93.93.17]) by mx1.freebsd.org (Postfix) with ESMTP id 3359A13C47E for ; Wed, 31 Jan 2007 16:24:59 +0000 (UTC) (envelope-from jorn@wcborstel.com) Received: from mail.wcborstel.com (mail [10.0.0.2]) by mail.wcborstel.com (Postfix) with ESMTP id 29C73434DB4; Wed, 31 Jan 2007 16:56:22 +0100 (CET) Received: by mail.wcborstel.com (Postfix, from userid 58) id DF9A1434DA9; Wed, 31 Jan 2007 16:56:21 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.1.7 (2006-10-05) on mail.wcborstel.com X-Spam-Level: X-Spam-Status: No, score=-1.4 required=5.0 tests=ALL_TRUSTED autolearn=ham version=3.1.7 X-Spam-Report: * -1.4 ALL_TRUSTED Passed through trusted hosts only via SMTP Received: from localhost (www.wcborstel.com [10.0.0.3]) by mail.wcborstel.com (Postfix) with ESMTP id AFA47434D9D; Wed, 31 Jan 2007 16:56:18 +0100 (CET) MIME-Version: 1.0 Date: Wed, 31 Jan 2007 16:56:18 +0100 From: Jorn Argelo To: Scott Killen In-Reply-To: <200701312340.38593.salkillen@internode.on.net> References: <200701312340.38593.salkillen@internode.on.net> Message-ID: <209e855bb68d64550ec4e384b3983664@mail.wcborstel.com> X-Sender: jorn@wcborstel.com User-Agent: RoundCube Webmail/0.1b Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Virus-Scanned: ClamAV using ClamSMTP Cc: freebsd-questions@freebsd.org 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: Wed, 31 Jan 2007 16:24:59 -0000 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. Jorn > > Regards > Scott K > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscribe@freebsd.org"