From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263422AbTIWU6k (ORCPT ); Tue, 23 Sep 2003 16:58:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263418AbTIWU6k (ORCPT ); Tue, 23 Sep 2003 16:58:40 -0400 Received: from pizda.ninka.net ([216.101.162.242]:44765 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id S263415AbTIWU6h (ORCPT ); Tue, 23 Sep 2003 16:58:37 -0400 Date: Tue, 23 Sep 2003 13:45:29 -0700 From: "David S. Miller" To: Grant Grundler Cc: bcrl@kvack.org, tony.luck@intel.com, davidm@hpl.hp.com, davidm@napali.hpl.hp.com, peter@chubb.wattle.id.au, ak@suse.de, peterc@gelato.unsw.edu.au, linux-ns83820@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: NS83820 2.6.0-test5 driver seems unstable on IA64 Message-Id: <20030923134529.7ea79952.davem@redhat.com> In-Reply-To: <20030923203819.GB8477@cup.hp.com> References: <20030923142925.A16490@kvack.org> <20030923185104.GA8477@cup.hp.com> <20030923115122.41b7178f.davem@redhat.com> <20030923203819.GB8477@cup.hp.com> X-Mailer: Sylpheed version 0.9.2 (GTK+ 1.2.6; sparc-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 23 Sep 2003 13:38:19 -0700 Grant Grundler wrote: > Given misaligned accesses are infrequent enough to affect > performance, it makes sense to do this in SW because > it reduces cost of the HW design/test/mfg cycles. Intel actually optimizes this on the P4, what is your response to that? Is Intel wasting they time? :-) > Ok. If the kernel networking stack used get_unaligned() in the one place > Peter originally found, x86/sparc64?/et al wouldn't see a difference. > It would avoid traps on ia64 and parisc. Bad idea? > Any other arches it might help/hurt on? It's needed on every access to every TCP and IP header portion for the case we're talking about in this thread, where the network device driver gives the networking a packet that ends up with unaligned IP and TCP headers. I once considered adding some get_unaligned() uses to the TCP option parsing code, guess who rejected that patch? It wasn't me, it was Linus himself and I came to learn that he's right on this one.