From owner-svn-src-head@FreeBSD.ORG Fri Mar 19 17:46:25 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 E49F91065673; Fri, 19 Mar 2010 17:46:25 +0000 (UTC) (envelope-from brde@optusnet.com.au) Received: from mail03.syd.optusnet.com.au (mail03.syd.optusnet.com.au [211.29.132.184]) by mx1.freebsd.org (Postfix) with ESMTP id 7AE868FC2C; Fri, 19 Mar 2010 17:46:25 +0000 (UTC) Received: from besplex.bde.org (c122-106-146-195.carlnfd1.nsw.optusnet.com.au [122.106.146.195]) by mail03.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id o2JHkLld007906 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 20 Mar 2010 04:46:23 +1100 Date: Sat, 20 Mar 2010 04:46:21 +1100 (EST) From: Bruce Evans X-X-Sender: bde@besplex.bde.org To: John Baldwin In-Reply-To: <201003191316.04620.jhb@freebsd.org> Message-ID: <20100320043345.J2151@besplex.bde.org> References: <7d6fde3d1003182333m336d52fbh987035a21568250d@mail.gmail.com> <9bbcef731003190913k4f3afbd8mb4e767c40433be8e@mail.gmail.com> <201003191316.04620.jhb@freebsd.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: src-committers@FreeBSD.org, svn-src-all@FreeBSD.org, Xin LI , Ivan Voras , svn-src-head@FreeBSD.org, Garrett Cooper Subject: Re: I486_CPU and I586_CPU removed from GENERIC kernel [was 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 17:46:26 -0000 On Fri, 19 Mar 2010, John Baldwin wrote: > On Friday 19 March 2010 12:13:00 pm Ivan Voras wrote: >> SSE in the userland you mean? Regardless, I don't think there is now >> reason for compiling everything as for i386. E.g. why not add at least >> -mtune=generic or even also -march=i686 to default gcc options? >> >> http://gcc.gnu.org/onlinedocs/gcc/i386-and-x86_002d64-Options.html > > I actually suggested using -mtune=i686 several years ago for i386. Using > -mtune=generic probably would be a good thing to use when CPUTYPE is not > specified for i386 and amd64 now. Er, isn't -mtune=generic the default in gcc-4.2? I once fought with gcc-4.2 to produce kernels with similar size and compile time to ones produced by gcc-3 (impossible for the runtime since gcc got another 40% slower and kernel source size and complications expanded another 40% even when the object size didn't bloat much). It took -i386 and a couple of other flags like -fno-inline-functions-called-once (the latter is also needed to unbreak debugging with ddb and profiling). The flags had very little difference on runtime efficiency, partly because I ran the kernels mainly on Athlons which run old i386-optimized code amazingly well but gain on benefits from i686 optimizations. Optimizing Athlon kernels for Athlons also makes little difference but I usually do it. Bruce