From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 25 May 2002 18:54:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 25 May 2002 18:54:00 -0400 Received: from ns.suse.de ([213.95.15.193]:63495 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id ; Sat, 25 May 2002 18:53:59 -0400 Date: Sun, 26 May 2002 00:53:59 +0200 From: Dave Jones To: "J.A. Magallon" Cc: Luca Barbieri , Marcelo Tosatti , Linux-Kernel ML Subject: Re: [PATCH] [2.4] [2.5] [i386] Add support for GCC 3.1 -march=pentium{-mmx,3,4} Message-ID: <20020526005359.E16102@suse.de> Mail-Followup-To: Dave Jones , "J.A. Magallon" , Luca Barbieri , Marcelo Tosatti , Linux-Kernel ML In-Reply-To: <1022360474.21238.5.camel@ldb> <20020525233739.GA2022@werewolf.able.es> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 26, 2002 at 01:37:39AM +0200, J.A. Magallon wrote: > Could you also split > Pentium-Pro/Celeron/Pentium-II CONFIG_M686 > into > > Pentium-Pro CONFIG_M686 > Pentium-II/Celeron CONFIG_MPENTIUMII > > Gcc-3.1 has also a -march=pentium2 specific target, that is not a synomym > for any other. There are also a few extra Athlon targets iirc. athlon-xp and the like, which I'm not sure the purpose of. Some gcc know-all want to clue me in to what these offer over -march=athlon ? > BTW, I think an option to enable -mmmx would also be useful. Nothing more, > because afaik sse is only floating point. Another interesting recently-added option which may be worth benchmarking on modern CPUs is the prefetch-loops option. In a lot of cases, the kernel 'knows better' and is adding the prefetches itself, but it may be interesting to see what difference gcc can make here. (More interesting would be examining the output to see *where* gcc is putting the prefetches) Given the immaturity of all these options, I'd doubt they're that good an idea for 2.4. Getting them tested during 2.5 may prove to get any bugs shaken out in time for $compiler_of_the_choice for 2.6 though. Dave -- | Dave Jones. http://www.codemonkey.org.uk | SuSE Labs