From owner-freebsd-questions@FreeBSD.ORG Mon Mar 1 21:24:58 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9DA0E1065673 for ; Mon, 1 Mar 2010 21:24:58 +0000 (UTC) (envelope-from anti_spam256@yahoo.ca) Received: from n12.bullet.mail.ac4.yahoo.com (n12.bullet.mail.ac4.yahoo.com [74.6.228.92]) by mx1.freebsd.org (Postfix) with SMTP id 3EC368FC0A for ; Mon, 1 Mar 2010 21:24:57 +0000 (UTC) Received: from [74.6.228.94] by n12.bullet.mail.ac4.yahoo.com with NNFMP; 01 Mar 2010 21:24:55 -0000 Received: from [76.13.10.162] by t1.bullet.mail.ac4.yahoo.com with NNFMP; 01 Mar 2010 21:24:55 -0000 Received: from [127.0.0.1] by omp103.mail.ac4.yahoo.com with NNFMP; 01 Mar 2010 21:24:55 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 118151.60287.bm@omp103.mail.ac4.yahoo.com Received: (qmail 9192 invoked by uid 60001); 1 Mar 2010 21:24:55 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.ca; s=s1024; t=1267478694; bh=gKkSmLXyRevhHVy1Mn3fNpNcN8yq2SnoQHsrA8b/p0k=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=DZu7++NxZlMf0EX6q1Tu1aJDszoOZ31dxDpwkPtvip4HiKLgstNStIAtLxET0z6/rRdaFYQ0JPQo65JEKMGavXAkExzy4/dqY+CJ6Oz728TZSlAZzSX+Tn7ouGHtbq/RM6tFSLQLkTfzdyW6Pvq3XizHJkzgbWZWaIsO8wDIleA= DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.ca; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=cs4jse6G6ek9PWrR8K85AbWso/3kCU1tpbbLrQN3zpU4Ba56RYp1XptMHyF4Iu8XZ8ciyxcfmltHSwDbl+n60aLl1Gi/AH9t1iV5wfguTzkpVB8uMAqBy0DnV3XPE8gPSg5IgAqg+S1ERkSOV9/NcFI+PIpAcW5zY/Ey4A2nfpI=; Message-ID: <997836.8570.qm@web65512.mail.ac4.yahoo.com> X-YMail-OSG: Nykp.34VM1mDza.xdAe5kVDZxyX7QZVWSfGaPM4XJbNMJNdrban9qlyUXPvoCmMEghN.gm0782S2kOTapffXmf.KZIzkyvsc4q9fqW2ZtPIm3B81rS282Ac0wibBe_YAR_CRTJZDaqheen8bv6Jm800Q8M41.TUWbYO7pMpwpimHnT7yiYHQtGnbU0LyE0gZAPkduCLtw8KqbUYWevawh.yYYptODSmKfxgVf4mmiZnt_LGe3sSGy.2HoK0Z2Qt8pJnD0txS.tYdBzNhe94Pha753RpNX0KJYLYRNOboXqYLQIu6psQKnDYAs96.AFqKeIibsz9zWE2gOWZNJy9HVSgMkGcGtaC9dOD7MpmBpFkrDZp_mcHiekYsSdQeaBwyoMKR Received: from [208.99.137.71] by web65512.mail.ac4.yahoo.com via HTTP; Mon, 01 Mar 2010 13:24:54 PST X-Mailer: YahooMailClassic/9.2.12 YahooMailWebService/0.8.100.260964 Date: Mon, 1 Mar 2010 13:24:54 -0800 (PST) From: James Phillips To: freebsd-questions@freebsd.org In-Reply-To: <20100301100655.B3D801065676@hub.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: Compiler Flags problem with core2 CPU 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: Mon, 01 Mar 2010 21:24:58 -0000 > Date: Sun, 28 Feb 2010 22:37:27 +0800 > From: Aaron Lewis > Subject: Re: Compiler Flags problem with core2 CPU > To: Paul B Mahol > Cc: freebsd-questions@freebsd.org > Message-ID: <4B8A7FA7.1070200@gmail.com> > Content-Type: text/plain; charset=3DISO-8859-1; > format=3Dflowed >=20 > Really ? It's bad to use custom flags to compile kernel , > why do you=20 > think so ? > I'd like to know more about this : ) >=20 > So setting optimize compiler flags is only useful for > userland stuff ? >=20 I laughed at your question because I remember reading somewhere that using = aggressive optimization options is a good way to find compiler bugs. I thin= k that extends of optimizations for "new" CPU architectures as well.=20 I also heard kernel code avoids MMX instructions for some reason: it may ha= ve to do with interrupt handling (fewer registers=3Dfaster?). x86 (and AMD6= 4) processors are backwards compatible, so you don't strictly need the late= st instructions. Regards, James Phillips =0A=0A=0A ____________________________________________________________= ______=0AThe new Internet Explorer=AE 8 - Faster, safer, easier. Optimized= for Yahoo! Get it Now for Free! at http://downloads.yahoo.com/ca/internet= explorer/