From owner-svn-src-head@FreeBSD.ORG Fri Mar 19 12:00:05 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8637E106566C; Fri, 19 Mar 2010 12:00:05 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 4E7F68FC28; Fri, 19 Mar 2010 12:00:05 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 0036A46B85; Fri, 19 Mar 2010 08:00:04 -0400 (EDT) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPA id 3F60D8A021; Fri, 19 Mar 2010 08:00:04 -0400 (EDT) From: John Baldwin To: Xin LI Date: Fri, 19 Mar 2010 07:59:56 -0400 User-Agent: KMail/1.12.1 (FreeBSD/7.3-CBSD-20100217; KDE/4.3.1; amd64; ; ) References: <201003190116.o2J1Gr2v094129@svn.freebsd.org> In-Reply-To: <201003190116.o2J1Gr2v094129@svn.freebsd.org> MIME-Version: 1.0 Message-Id: <201003190759.56385.jhb@freebsd.org> Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Fri, 19 Mar 2010 08:00:04 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-1.6 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r205307 - head/sys/i386/conf X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Mar 2010 12:00:05 -0000 On Thursday 18 March 2010 9:16:53 pm Xin LI wrote: > Author: delphij > Date: Fri Mar 19 01:16:53 2010 > New Revision: 205307 > URL: http://svn.freebsd.org/changeset/base/205307 > > Log: > SSE is enabled by default about 5 years ago so there is no point pretending > that we support I486 and I586 CPUs in the GENERIC kernel, users wants these > support would have to build a custom kernel to explicitly disable SSE > anyways. > > MFC after: 1 month No, this is wrong. Revert this. We do _not_ unconditionally use SSE in the kernel. GENERIC should run just fine on a 486. If it doesn't, that should be fixed, but I have not seen any reports to the contrary. In general we do not use any floating-point / MMX / SSE instructions in the kernel as our FPU context-saving code doesn't support it. All the x86 world is not rack-mounted 64-bit servers. We should not remove support for non-686 CPUs for no good reason. 486 CPUs have cmpxchg and xadd so are perfectly adequate. -- John Baldwin