From owner-freebsd-amd64@FreeBSD.ORG Thu Jul 28 12:13:55 2005 Return-Path: X-Original-To: freebsd-amd64@freebsd.org Delivered-To: freebsd-amd64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7B60816A41F for ; Thu, 28 Jul 2005 12:13:55 +0000 (GMT) (envelope-from des@des.no) Received: from tim.des.no (tim.des.no [194.63.250.121]) by mx1.FreeBSD.org (Postfix) with ESMTP id 06D3743D48 for ; Thu, 28 Jul 2005 12:13:54 +0000 (GMT) (envelope-from des@des.no) Received: from tim.des.no (localhost [127.0.0.1]) by spam.des.no (Postfix) with ESMTP id C06486145; Thu, 28 Jul 2005 14:13:49 +0200 (CEST) Received: from xps.des.no (des.no [80.203.228.37]) by tim.des.no (Postfix) with ESMTP id 4FD1360F8; Thu, 28 Jul 2005 14:13:49 +0200 (CEST) Received: by xps.des.no (Postfix, from userid 1001) id 2B15D33D48; Thu, 28 Jul 2005 14:13:49 +0200 (CEST) To: ray@redshift.com References: <3.0.1.32.20050728013152.00a4d188@pop.redshift.com> From: des@des.no (=?iso-8859-1?q?Dag-Erling_Sm=F8rgrav?=) Date: Thu, 28 Jul 2005 14:13:49 +0200 In-Reply-To: <3.0.1.32.20050728013152.00a4d188@pop.redshift.com> (ray@redshift.com's message of "Thu, 28 Jul 2005 01:31:52 -0700") Message-ID: <86mzo7yvpe.fsf@xps.des.no> User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable X-Spam-Tests: ALL_TRUSTED,AWL,BAYES_00 X-Spam-Learn: ham X-Spam-Score: -5.3/5.0 X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on tim.des.no Cc: freebsd-amd64@freebsd.org Subject: Re: Benchmarks: AMD64 vs i386 on Dual 246 Opteron X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Jul 2005 12:13:55 -0000 ray@redshift.com writes: > While this sounded like a long shot, I loaded FreeBSD 5.4 i386 on > the machine and after applying the exact same configuration to the > OS, Apache, PHP and MySQL, re-ran the benchmarks. Much to my > surprise, just changing the OS from 64 bit to 32 bit caused the > machine to double in speed. The results are attached in an Excel > spreadsheet. So the exact same machine, running the identical > configuration, performed roughly twice as fast when running FreeBSD > 5.4 i386 vs FreeBSD 5.4 AMD64. Something about this seems so wrong > to me :-) 64-bit code uses up to twice as much CPU cache and twice as many memory accesses to do the same work as the equivalent 32-bit code. DES --=20 Dag-Erling Sm=F8rgrav - des@des.no