From owner-freebsd-alpha@FreeBSD.ORG Fri Jan 14 18:26:57 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 B514516A4CE; Fri, 14 Jan 2005 18:26:57 +0000 (GMT) Received: from smtp-vbr4.xs4all.nl (smtp-vbr4.xs4all.nl [194.109.24.24]) by mx1.FreeBSD.org (Postfix) with ESMTP id E551443D1F; Fri, 14 Jan 2005 18:26:56 +0000 (GMT) (envelope-from wb@freebie.xs4all.nl) Received: from freebie.xs4all.nl (freebie.xs4all.nl [213.84.32.253]) by smtp-vbr4.xs4all.nl (8.12.11/8.12.11) with ESMTP id j0EIQt95059016; Fri, 14 Jan 2005 19:26:55 +0100 (CET) (envelope-from wb@freebie.xs4all.nl) Received: from freebie.xs4all.nl (localhost [127.0.0.1]) by freebie.xs4all.nl (8.13.1/8.12.9) with ESMTP id j0EIQteM000689; Fri, 14 Jan 2005 19:26:55 +0100 (CET) (envelope-from wb@freebie.xs4all.nl) Received: (from wb@localhost) by freebie.xs4all.nl (8.13.1/8.13.1/Submit) id j0EIQtOC000688; Fri, 14 Jan 2005 19:26:55 +0100 (CET) (envelope-from wb) Date: Fri, 14 Jan 2005 19:26:55 +0100 From: Wilko Bulte To: John Baldwin Message-ID: <20050114182655.GC630@freebie.xs4all.nl> References: <16866.32790.398095.651691@canoe.dclg.ca> <20050114002651.GD29445@dragon.nuxi.com> <20050114074336.GA97061@freebie.xs4all.nl> <200501141043.00568.jhb@FreeBSD.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200501141043.00568.jhb@FreeBSD.org> X-OS: FreeBSD 4.11-RC2 User-Agent: Mutt/1.5.6i X-Virus-Scanned: by XS4ALL Virus Scanner cc: freebsd-alpha@FreeBSD.org Subject: Re: processor type. X-BeenThere: freebsd-alpha@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list 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 18:26:57 -0000 On Fri, Jan 14, 2005 at 10:43:00AM -0500, John Baldwin wrote.. > On Friday 14 January 2005 02:43 am, Wilko Bulte wrote: > > On Thu, Jan 13, 2005 at 04:26:51PM -0800, David O'Brien wrote.. > > > > > 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-Al > > >pha-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. > > > > Any idea how drastic -mtune=ev6 would change things on a DS10 (to name > > a random box ;-) ? > > > > Am I correct in assuming that -mcpu=ev4 will result in not using the BWX > > etc of the newer CPUs? And that -mcpu=ev6 will result in code that does > > not run on anything older than EV6 due to missing instructions etc? > > Yes. Note that setting CPUTYPE in make.conf gets all the right flags set for> you automagically. I think I need to go and just investigate, but let me fire another silly question: Where does this kind of option get set for a make release? I need to avoid any /etc/make.conf stuff making its way into the Alpha releases I build ;-) I sort of expect the settings in /etc/make.conf to only apply to building world and not to building release. Correct? -- Wilko Bulte wilko@FreeBSD.org