From owner-freebsd-questions@FreeBSD.ORG Thu Mar 15 05:39:03 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 848F616A402 for ; Thu, 15 Mar 2007 05:39:03 +0000 (UTC) (envelope-from kline@tao.thought.org) Received: from tao.thought.org (dsl231-043-140.sea1.dsl.speakeasy.net [216.231.43.140]) by mx1.freebsd.org (Postfix) with ESMTP id 0593A13C43E for ; Thu, 15 Mar 2007 05:39:02 +0000 (UTC) (envelope-from kline@tao.thought.org) Received: from tao.thought.org (localhost [127.0.0.1]) by tao.thought.org (8.13.8/8.13.1) with ESMTP id l2F5dA39062409; Wed, 14 Mar 2007 21:39:10 -0800 (PST) (envelope-from kline@tao.thought.org) Received: (from kline@localhost) by tao.thought.org (8.13.8/8.13.1/Submit) id l2F5d93n062408; Wed, 14 Mar 2007 21:39:09 -0800 (PST) (envelope-from kline) Date: Wed, 14 Mar 2007 21:39:09 -0800 From: Gary Kline To: Karol Kwiatkowski Message-ID: <20070315053909.GD62026@thought.org> References: <20070315011651.GA1524@thought.org> <45F8A5BE.20704@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45F8A5BE.20704@gmail.com> User-Agent: Mutt/1.4.2.2i X-Organization: Thought Unlimited. Public service Unix since 1986. X-Of_Interest: Observing twenty years of service to the Unix community Cc: Gary Kline , freebsd-questions@freebsd.org Subject: Re: Optimizationn questions? 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: Thu, 15 Mar 2007 05:39:03 -0000 On Thu, Mar 15, 2007 at 02:47:42AM +0100, Karol Kwiatkowski wrote: > Gary Kline wrote: > > Two quick one for kernel and/or compiler wizards: first, is > > a 400Mz processor considered a 586 (for my KERNELCONF file)? > > That depends on processor architecture rather than clock frequency. Have > a look at dmesg output - for example, Intel Celeron 400Mhz is a 686 > class processor (I686_CPU in the kernel configuration file): > > % dmesg > % [...] > % CPU: Pentium II/Pentium II Xeon/Celeron (400.91-MHz 686-class CPU) > % [...] Dunno anything about the Xeon, but the Kayak is nuilt like a tank and has got to be == a 686 also. I'll check my dmesg too. --Until very recently, I've gone wit the default (i386??); like: how much faster is gcc tweaking going to be? I guess I'll find out! > > > Second, is it safe to do a buildworld with -O3? If there are > > stability concerns, I'll go with the default when I rebuild my > > 6.2 systems. > > If you're going to do stability/performance/compatibility tests go > ahead. In any other situation just stick with the defaults, which on > 6.2-RELEASE for my Celeron are: > > # (cd /usr/src && make -V CFLAGS ) > -O2 -fno-strict-aliasing -pipe -march=pentiumpro > > Note that '-march=pentiumpro' comes from setting 'CPUTYPE=i686' in > /etc/make.conf (examples in /usr/share/examples/etc/make.conf). Martin Tournoij pointed out what (fine-print) I didn't see [never read/very seldom read] that the world and kernel should be left at O, O2 or their default. I signal to gcc to unroll loops and know that the compiler writers are going to use their learned and practical wisdom regarding loop unrolling... . > > HTH, It has and thanks much. Gotta rebuild, but no big deal! gary > > Karol > > -- > Karol Kwiatkowski > OpenPGP 0x06E09309 > -- Gary Kline kline@thought.org www.thought.org Public Service Unix