Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 25 Feb 2002 02:48:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 25 Feb 2002 02:48:45 -0500 Received: from nat-pool-rdu.redhat.com ([66.187.233.200]:52470 "EHLO devserv.devel.redhat.com") by vger.kernel.org with ESMTP id ; Mon, 25 Feb 2002 02:48:37 -0500 Date: Mon, 25 Feb 2002 02:48:17 -0500 From: Jakub Jelinek To: Luigi Genoni Cc: "Paul G. Allen" , "Linux kernel developer's mailing list" Subject: Re: gcc-2.95.3 vs gcc-3.0.4 Message-ID: <20020225024817.Q2434@devserv.devel.redhat.com> Reply-To: Jakub Jelinek In-Reply-To: <3C775FEF.BDA0253C@randomlogic.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from kernel@Expansa.sns.it on Mon, Feb 25, 2002 at 01:07:42AM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 25, 2002 at 01:07:42AM +0100, Luigi Genoni wrote: > At this link: > > http://www.cs.utk.edu/~rwhaley/ATLAS/gcc30.html > > you can find an interesting explanation why code compiled with gcc 3.0 is > mostly slower than code compiled with gcc 2.95 on x86 CPUs (but it is > really faster on other platforms like alpha and sparc64). > > basically the main reasons semm to be the scheduler algorithm and the fpu > stack handling, but I suggest to read the full study. > > > I would be interested to know if this apply to gcc 3.1 too. Well, concerning reg-stack, you can completely get away without it in 3.1 by using -mfpmath=sse if you are targeting Pentium 3,4 or Athlon 4,xp,mp (for float math, for higher precision only for Pentium 4). Jakub - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/