From owner-freebsd-arch@FreeBSD.ORG Fri Mar 19 18:49:27 2010 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DCA1C1065686 for ; Fri, 19 Mar 2010 18:49:27 +0000 (UTC) (envelope-from julian@elischer.org) Received: from out-0.mx.aerioconnect.net (out-0-26.mx.aerioconnect.net [216.240.47.86]) by mx1.freebsd.org (Postfix) with ESMTP id BF8848FC20 for ; Fri, 19 Mar 2010 18:49:27 +0000 (UTC) Received: from idiom.com (postfix@mx0.idiom.com [216.240.32.160]) by out-0.mx.aerioconnect.net (8.13.8/8.13.8) with ESMTP id o2JIaCnw022143; Fri, 19 Mar 2010 11:36:12 -0700 X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e X-Client-Authorized: MaGic Cook1e Received: from julian-mac.elischer.org (h-67-100-89-137.snfccasy.static.covad.net [67.100.89.137]) by idiom.com (Postfix) with ESMTP id EB6102D601C; Fri, 19 Mar 2010 11:36:11 -0700 (PDT) Message-ID: <4BA3C41F.3000404@elischer.org> Date: Fri, 19 Mar 2010 11:36:15 -0700 From: Julian Elischer User-Agent: Thunderbird 2.0.0.24 (Macintosh/20100228) MIME-Version: 1.0 To: John Baldwin References: <4BA2CE17.2050105@delphij.net> <201003190751.26767.jhb@freebsd.org> In-Reply-To: <201003190751.26767.jhb@freebsd.org> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.67 on 216.240.47.51 Cc: d@delphij.net, freebsd-arch@freebsd.org Subject: Re: [PATCH] Utilize i686, SSE and MMX by default on FreeBSD/i386 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Mar 2010 18:49:27 -0000 John Baldwin wrote: > On Thursday 18 March 2010 9:06:31 pm Xin LI wrote: >> Hi, >> >> I think it doesn't really make sense to by default use MACHINE_CPU=i486 >> when the kernel is built with SSE by default today. >> >> Attached patch uses i686 SSE MMX by default, the user can always change >> the default setting by overriding CPUTYPE (they have to do it as SSE is >> enabled by default for several years). > > The kernel is only built with support for userland applications using SSE, it > does not _use_ SSE. Similarly, the kernel is built with support for PG_NX > provided on 64-bit processors, but it does not do so by failing to support > older 32-bit processors. I think this change is premature. Users can already > set CPUTYPE in make.conf. Also, most modern x86 server-class machines are > 64-bit in which case they would be running FreeBSD/amd64 and using SSE > already. > and a lot of low power boxes (e.g. soekris) are 586 class.