From owner-freebsd-net@FreeBSD.ORG Tue Sep 15 07:38:33 2009 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 75C4E1065670 for ; Tue, 15 Sep 2009 07:38:33 +0000 (UTC) (envelope-from peterjeremy@acm.org) Received: from mail13.syd.optusnet.com.au (mail13.syd.optusnet.com.au [211.29.132.194]) by mx1.freebsd.org (Postfix) with ESMTP id 0B59F8FC1C for ; Tue, 15 Sep 2009 07:38:32 +0000 (UTC) Received: from server.vk2pj.dyndns.org (c122-106-250-30.belrs3.nsw.optusnet.com.au [122.106.250.30]) by mail13.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id n8F7cUri017969 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 15 Sep 2009 17:38:31 +1000 X-Bogosity: Ham, spamicity=0.000000 Received: from server.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by server.vk2pj.dyndns.org (8.14.3/8.14.3) with ESMTP id n8F7cUR0048762; Tue, 15 Sep 2009 17:38:30 +1000 (EST) (envelope-from peter@server.vk2pj.dyndns.org) Received: (from peter@localhost) by server.vk2pj.dyndns.org (8.14.3/8.14.3/Submit) id n8F7cUir048761; Tue, 15 Sep 2009 17:38:30 +1000 (EST) (envelope-from peter) Date: Tue, 15 Sep 2009 17:38:30 +1000 From: peterjeremy@acm.org To: Barney Cordoba Message-ID: <20090915073830.GC48679@server.vk2pj.dyndns.org> References: <4AACEF9E.90303@mail.ru> <94372.57247.qm@web63906.mail.re1.yahoo.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bKyqfOwhbdpXa4YI" Content-Disposition: inline In-Reply-To: <94372.57247.qm@web63906.mail.re1.yahoo.com> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.20 (2009-06-14) Cc: freebsd-net@freebsd.org Subject: Re: [POLLING] strange interrupt/system load X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Sep 2009 07:38:33 -0000 --bKyqfOwhbdpXa4YI Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2009-Sep-13 07:19:24 -0700, Barney Cordoba wr= ote: >64bits must be faster than 32bits is patently misguided. My rule of=20 >thumb is that if I don't need 64bits for something, I avoid it. It's not quite that cut-and-dry. The 64-bit ISA is significantly different to the 32-bit ISA and has different subroutine calling conventions. Yes, you do need to lug 64-bit pointers around but the overall codesize is comparable (looking at /usr/bin and /lib suggests about a 5% increase in size going from i386 to amd64) - a lot of this is probably because amd64 has a 16-bit offset mode so there's much less need for 32-bit offsets. Having twice as many registers is a win in some areas (less spilling to memory) and a loss in others (more state to save/restore on a context switch). If performance is critical, it's probably worthwhile benchmarking both i386 and amd64 variants and seeing which works best for you. --=20 Peter Jeremy --bKyqfOwhbdpXa4YI Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.12 (FreeBSD) iEYEARECAAYFAkqvRHYACgkQ/opHv/APuIeIuACdHSMLn1nZ/m/H38sZTzDgE8Uv Y4IAn1G8CPnLW2h4IfeRvIXlmET+oMOn =vbdQ -----END PGP SIGNATURE----- --bKyqfOwhbdpXa4YI--