From owner-freebsd-questions@FreeBSD.ORG Sat Apr 24 18:02:42 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DE93A1065672 for ; Sat, 24 Apr 2010 18:02:42 +0000 (UTC) (envelope-from freebsd-questions@m.gmane.org) Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by mx1.freebsd.org (Postfix) with ESMTP id 660B58FC12 for ; Sat, 24 Apr 2010 18:02:42 +0000 (UTC) Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1O5jgd-00079Z-Dx for freebsd-questions@freebsd.org; Sat, 24 Apr 2010 20:02:39 +0200 Received: from pool-71-166-133-192.washdc.east.verizon.net ([71.166.133.192]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 24 Apr 2010 20:02:39 +0200 Received: from nightrecon by pool-71-166-133-192.washdc.east.verizon.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 24 Apr 2010 20:02:39 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-questions@freebsd.org connect(): No such file or directory From: Michael Powell Followup-To: gmane.os.freebsd.questions Date: Sat, 24 Apr 2010 14:05:14 -0400 Lines: 39 Message-ID: References: <201004241744.47794.jmc-freebsd2@milibyte.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: pool-71-166-133-192.washdc.east.verizon.net Subject: Re: Which CPUTYPE in make.conf? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 24 Apr 2010 18:02:42 -0000 C. P. Ghost wrote: > On Sat, Apr 24, 2010 at 7:32 PM, Michael Powell > wrote: >> I think this matters more to third party ports software builds than it >> does the system. I thought that large pieces of the kernel were designed >> to not make much, if any, use the various SIMD extensions. Maybe this has >> changed and I'm behind the times. > > I wouldn't bother setting CPUTYPE at all. It's more trouble than it's > worth. Actually, I've been setting CPUTYPE for many years and have never had any trouble as a result. I've always used the form: CPUTYPE?= blah instead of CPUTYPE= without the question mark. > And you're right: for most ports and for the whole system, it doesn't > really matter. If you have a very specific port that needs particular > tuning, it has either already been tuned individually by the port > maintainer, or you could apply more optimizations yourself (which would > likely require a specially compiled tool chain, when -O with > the base gcc/binutils isn't enough). I have also used CFLAGS= -O2 -pipe COPTFLAGS= -O2 -pipe. About the only place it will really make any difference is in some multimedia apps. And you're right that if needed the port maintainer has already taken care of this. > Unless you have a very specific need, better leave CPUTYPE alone. Thing is, any performance increase is only going to be very small. So small the difference can probably not be seen subjectively. I'll do it as long as it creates no problem; if any problem were to arise over this I'd kill it in a heartbeat and not fuss over it. It is a point of diminishing returns. [snip] -Mike