From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264374AbUBHXGt (ORCPT ); Sun, 8 Feb 2004 18:06:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264383AbUBHXGt (ORCPT ); Sun, 8 Feb 2004 18:06:49 -0500 Received: from imladris.demon.co.uk ([193.237.130.41]:7296 "EHLO baythorne.infradead.org") by vger.kernel.org with ESMTP id S264374AbUBHXGs (ORCPT ); Sun, 8 Feb 2004 18:06:48 -0500 Subject: Re: When should we use likely() / unlikely() / get_unaligned() ? From: David Woodhouse To: Rusty Russell Cc: linux-kernel@vger.kernel.org, matthew@wil.cx, davem@redhat.com In-Reply-To: <20040208230331.79FEB2C003@lists.samba.org> References: <20040208230331.79FEB2C003@lists.samba.org> Content-Type: text/plain Message-Id: <1076281602.8563.1.camel@imladris.demon.co.uk> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.5 (1.4.5-8.dwmw2.2) Date: Sun, 08 Feb 2004 23:06:43 +0000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2004-02-09 at 10:00 +1100, Rusty Russell wrote: > > we now support architectures in 2.6 where alignment fixups _cannot_ happen, > > and the cost of the 'exception' case should be considered infinite. > > Um, we do? I thought it was compulsory in the kernel, otherwise > networking breaks on packets w/ wierd hardware headers. We do. It breaks. I'm trying to come up with a solution for it which actually lets us optimise elsewhere too, and hence has at least a whelk's chance in a supernova of being accepted... :) -- dwmw2