Date: Thu, 14 Dec 2006 07:55:17 -0800 From: "David O'Brien" <obrien@freebsd.org> To: Scott Long <scottl@samsco.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, mjacob@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/amd64/conf GENERIC Message-ID: <20061214155517.GA21748@dragon.NUXI.org> In-Reply-To: <4580DE4E.3080008@samsco.org> References: <200612140357.kBE3vY0Q053458@repoman.freebsd.org> <4580CD6A.5090802@samsco.org> <20061213201031.T26658@ns1.feral.com> <4580D3BB.7060504@samsco.org> <20061213210116.P26879@ns1.feral.com> <4580DE4E.3080008@samsco.org>
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On Wed, Dec 13, 2006 at 08:13:24PM -0800, mjacob@freebsd.org wrote: > Secondly, I would *like* to have SMP on as a default in RELENG_6 for > amd64, as it would avoid doing what I've done twice already- fresh > sysinstall may or may not have installed an SMP kernel but going off and > building GENERIC then lost me my SMP. It's sort a violation of POLA. Rather close what happened to me and what lead to the commit. On Wed, Dec 13, 2006 at 10:17:02PM -0700, Scott Long wrote: > mjacob@freebsd.org wrote: > > Scott Long wrote: > > > There wasn't a full switchover to SMP at 6.0 because an SMP kernel > > > on a UP system incurs a measurable runtime overhead, and we wanted > > > to present a system that showed the best of FreeBSD to people who > > > wanted to run it Then why is sparc64's GENERIC kernel SMP in RELENG_6? > > But David's point is that most AMD64 boxes *are* SMP, not UP. Is > > that wrong? > > 1. There are plenty of single core Opterons and Athlon64 chips still > in service. A few points: * FreeBSD is predominately a server OS, not home desktop OS. * Practically all single core Opteron's are used in multi-socket systems. There are very, very few Opteron single socket, single core Opteron's in service as there are only a very small handful of single socket 940-pin motherboards. * Most Athlon64 single-core CPU's are run in 32-bit "i386" mode. FreeBSD/i386 isn't the platform I (and presumably Matt) are talking about. > Maybe AMD sells more SMP systems now than UP systems, but their prior > sales of UP systems didn't magically disappear overnight. This is not an AMD-only situation. Intel has been selling dual-core processors since 18 April 2005, and now sells quad-core processors. Also, Intel kept Long Model (i.e., EM64T) to the server/workstation segment until its dual-core processors. For instance, most Intel laptops cannot run FreeBSD/AMD64. -- -- David (obrien@FreeBSD.org)
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