From owner-freebsd-alpha@FreeBSD.ORG Fri Jan 14 00:27:00 2005 Return-Path: Delivered-To: freebsd-alpha@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2930E16A4CE for ; Fri, 14 Jan 2005 00:27:00 +0000 (GMT) Received: from dragon.nuxi.com (trang.nuxi.com [66.93.134.19]) by mx1.FreeBSD.org (Postfix) with ESMTP id DF29943D31 for ; Fri, 14 Jan 2005 00:26:59 +0000 (GMT) (envelope-from obrien@NUXI.com) Received: from dragon.nuxi.com (obrien@localhost [127.0.0.1]) by dragon.nuxi.com (8.13.1/8.13.1) with ESMTP id j0E0Qpe7052655; Thu, 13 Jan 2005 16:26:51 -0800 (PST) (envelope-from obrien@dragon.nuxi.com) Received: (from obrien@localhost) by dragon.nuxi.com (8.13.1/8.13.1/Submit) id j0E0Qps1052654; Thu, 13 Jan 2005 16:26:51 -0800 (PST) (envelope-from obrien) Date: Thu, 13 Jan 2005 16:26:51 -0800 From: "David O'Brien" To: David Gilbert Message-ID: <20050114002651.GD29445@dragon.nuxi.com> References: <16866.32790.398095.651691@canoe.dclg.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16866.32790.398095.651691@canoe.dclg.ca> User-Agent: Mutt/1.4.1i X-Operating-System: FreeBSD 6.0-CURRENT Organization: The NUXI BSD Group X-Pgp-Rsa-Fingerprint: B7 4D 3E E9 11 39 5F A3 90 76 5D 69 58 D9 98 7A X-Pgp-Rsa-Keyid: 1024/34F9F9D5 cc: freebsd-alpha@freebsd.org Subject: Re: processor type. X-BeenThere: freebsd-alpha@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: freebsd-alpha@freebsd.org List-Id: Porting FreeBSD to the Alpha List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 14 Jan 2005 00:27:00 -0000 On Mon, Jan 10, 2005 at 08:16:06AM -0500, David Gilbert wrote: > I see in the compiler lines crawling by that gcc is asked to optimize > for 'EV5' while being compatible with 'EV4'. My Alpha is an EV4 --- > I'm wondering if I would see better performance with a different flag > there, but the gcc manual doesn't even acknowledge the existance of > the options that are in use, let alone the available options. It doens't??? >From /usr/share/mk/bsd.cpu.mk: . elif ${MACHINE_ARCH} == "alpha" _CPUCFLAGS = -mcpu=ev4 -mtune=ev5 http://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/DEC-Alpha-Options.html#DEC-Alpha-Options clearly tells: -mcpu=cpu_type Set the instruction set and instruction scheduling parameters for machine type cpu_type. You can specify either the EV style name or the corresponding chip number. GCC supports scheduling parameters for the EV4, EV5 and EV6 family of processors. -mtune=cpu_type Set only the instruction scheduling parameters for machine type cpu_type. The instruction set is not changed. That said, you should remove the -mtune=ev5 or change it to -mtune=ev4. My guess is you won't notice a difference, but this this change will produce the best code for your machine. -- -- David (obrien@FreeBSD.org)