Date: Fri, 12 Oct 2007 03:21:30 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Artem Kuchin <matrix@itlegion.ru> Cc: freebsd-stable@freebsd.org Subject: Re: how to compiel kernel and world to maxium optimization Message-ID: <20071012102130.GA93158@eos.sc1.parodius.com> In-Reply-To: <024901c80cb6$f49696b0$0c00a8c0@Artem> References: <024901c80cb6$f49696b0$0c00a8c0@Artem>
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On Fri, Oct 12, 2007 at 02:02:09PM +0400, Artem Kuchin wrote: > The point is that if i have Xeon HT cpus (not very new, but > definitelly not Pentium PRO :) i can build kernel and world > using insttructions for this CPU and optimization for it, so > i would get myself a speedy system and less memory hungry, right? Not necessarily. This assumption is often driven by what I like to call the "Gentoo mentality". Throwing on optimisations and assuming the system will "magically be more efficient" is not how you gain efficiency; I grow tired of seeing programs mindlessly set -O3 and other insanities, based purely on assumptions. > The only option known to me which is related to the isee is cpu > setting in kernel config file. Anything else? By using CPUTYPE in /etc/make.conf. /usr/share/examples/etc/make.conf lists value values. For a Xeon, you should probably use "nocona", assuming the Xeon model you have supports SSE3 instructions. Other- wise, use "prescott". Also, very important: use CPUTYPE?=value and not CPUTYPE=value. There's a thread on the values (focusing around amd64, but the same applies to i386) below; see the post from Mike Meyer. http://groups.google.com/group/lucky.freebsd.amd64/browse_thread/thread/79b9b9664cc87ae5/6eb86b7ede208173?lnk=st&q=freebsd+cputype+xeon#6eb86b7ede208173 -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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