From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755260AbXHRCBW (ORCPT ); Fri, 17 Aug 2007 22:01:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751280AbXHRCBJ (ORCPT ); Fri, 17 Aug 2007 22:01:09 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:49634 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751260AbXHRCBH (ORCPT ); Fri, 17 Aug 2007 22:01:07 -0400 Subject: Re: [PATCH] i386: optimize memset of 6 and 8 bytes From: Arjan van de Ven To: Stephen Hemminger Cc: "David S. Miller" , Andrew Morton , linux-kernel@vger.kernel.org, netdev@vger.kernel.org In-Reply-To: <20070817185452.5cbf60c4@freepuppy.rosehill.hemminger.net> References: <20070817165030.5455f761@freepuppy.rosehill.hemminger.net> <1187401774.2789.0.camel@laptopd505.fenrus.org> <20070817185452.5cbf60c4@freepuppy.rosehill.hemminger.net> Content-Type: text/plain Organization: Intel International BV Date: Fri, 17 Aug 2007 18:57:00 -0700 Message-Id: <1187402220.2789.2.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.11.6.1 (2.11.6.1-1.fc8) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2007-08-17 at 18:54 -0700, Stephen Hemminger wrote: > On Fri, 17 Aug 2007 18:49:34 -0700 > Arjan van de Ven wrote: > > > > > On Fri, 2007-08-17 at 16:50 -0700, Stephen Hemminger wrote: > > > Tne network code does memset for 6 and 8 byte values, that can easily > > > be optimized into simple assignments without string instructions. > > > > > > so... question. > > Why are we doing this by hand? Wouldn't gcc just generate this code in > > the first place (when using __builtin_memset)? I very much suspect it > > would (and if some version doesn't.... we really ought to get that > > fixed) > > i386 and x86_64 are not using __builtin_memset, as least from the > code that I see generated. .. maybe we should just fix it that way then? -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org