From owner-freebsd-stable@FreeBSD.ORG Fri Aug 8 23:12:40 2008 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 3B3391065673 for ; Fri, 8 Aug 2008 23:12:40 +0000 (UTC) (envelope-from peterjeremy@optushome.com.au) Received: from mail12.syd.optusnet.com.au (mail12.syd.optusnet.com.au [211.29.132.193]) by mx1.freebsd.org (Postfix) with ESMTP id C09F38FC08 for ; Fri, 8 Aug 2008 23:12:39 +0000 (UTC) (envelope-from peterjeremy@optushome.com.au) Received: from server.vk2pj.dyndns.org (c122-106-215-175.belrs3.nsw.optusnet.com.au [122.106.215.175]) by mail12.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id m78NCaJU022645 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 9 Aug 2008 09:12:38 +1000 Received: from server.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by server.vk2pj.dyndns.org (8.14.2/8.14.2) with ESMTP id m78NCXWD057232 for ; Sat, 9 Aug 2008 09:12:33 +1000 (EST) (envelope-from peter@server.vk2pj.dyndns.org) Received: (from peter@localhost) by server.vk2pj.dyndns.org (8.14.2/8.14.2/Submit) id m78NCXi3057231 for freebsd-stable@freebsd.org; Sat, 9 Aug 2008 09:12:33 +1000 (EST) (envelope-from peter) Date: Sat, 9 Aug 2008 09:12:33 +1000 From: Peter Jeremy To: freebsd-stable@freebsd.org Message-ID: <20080808231232.GK64458@server.vk2pj.dyndns.org> References: <1EE0EC59-C48C-4B07-B08E-77BE388BBDE1@develooper.com> <200808081236.m78CagPH015579@lurza.secnetix.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="cz6wLo+OExbGG7q/" Content-Disposition: inline In-Reply-To: <200808081236.m78CagPH015579@lurza.secnetix.de> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.18 (2008-05-17) Subject: Re: i386 vs amd64? 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: Fri, 08 Aug 2008 23:12:40 -0000 --cz6wLo+OExbGG7q/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2008-Aug-08 14:36:42 +0200, Oliver Fromme wrote: >For example, in amd64 mode there are twice as many CPU >registers available, enabling better optimizations for >the C compiler. Furthermore those registers are twice >as long, which means that 64bit quantities can be handled >with single processor instructions. OTOH, this means roughly 4 times as much processor state to save and restore on a context switch. It also means that longs and pointers are 64-bits instead of 32-bits, which makes executables larger (if you compare executables and libraries on disk between FreeBSD/i386 and FreeBSD/amd64, the latter are 10-15% larger). The VSZ of amd64 executables _appears_ significantly larger due to a bug in binutils and our rtld but this space is never referenced. >That doesn't necessarily mean that code will always run >faster in amd64 mode. There have been reports of certain >edge cases. But in general, amd64 code is faster. As always, the best benchmark is your own application mix. >Bottom line: Install FreeBSD/amd64, unless you have >_specific_ reasons to stay with i386. Keep in mind that, for most things, FreeBSD/amd64 can happily run 32-bit Linux and FreeBSD/i386 executables (though there's no easy way to build FreeBSD/i386 executables on FreeBSD/amd64). This does not extend to KLDs so 3rd-party 32-bit KLDs (eg the nVIDIA graphics driver). --=20 Peter Jeremy Please excuse any delays as the result of my ISP's inability to implement an MTA that is either RFC2821-compliant or matches their claimed behaviour. --cz6wLo+OExbGG7q/ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkic0uAACgkQ/opHv/APuIfZmACeJniSOtR+N1249Wb+d6go7M6H LHQAniwiTItV4IlZ34ZyZLqB4K9sRgdW =72pY -----END PGP SIGNATURE----- --cz6wLo+OExbGG7q/--