From owner-cvs-all@FreeBSD.ORG  Mon Jul  4 10:06:41 2005
Return-Path: <owner-cvs-all@FreeBSD.ORG>
X-Original-To: cvs-all@freebsd.org
Delivered-To: cvs-all@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 535E916A41C;
	Mon,  4 Jul 2005 10:06:41 +0000 (GMT)
	(envelope-from grehan@freebsd.org)
Received: from liberty.onthenet.com.au (liberty.OntheNet.com.au
	[203.22.124.10])
	by mx1.FreeBSD.org (Postfix) with ESMTP id DC69B43D49;
	Mon,  4 Jul 2005 10:06:40 +0000 (GMT)
	(envelope-from grehan@freebsd.org)
Received: from [203.144.2.137] (CPE-2-137.dsl.OntheNet.net [203.144.2.137])
	by liberty.onthenet.com.au (8.12.9 - 20030918/8.12.9) with ESMTP id
	j64A6d7v063142; Mon, 4 Jul 2005 20:06:39 +1000 (EST)
	(envelope-from grehan@freebsd.org)
Message-ID: <42C90A29.2030706@freebsd.org>
Date: Mon, 04 Jul 2005 20:06:33 +1000
From: Peter Grehan <grehan@freebsd.org>
User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.2) Gecko/20041016
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: Robert Watson <rwatson@freebsd.org>
References: <200507022313.j62NDWYC028248@repoman.freebsd.org>
	<42C90419.8070509@freebsd.org>
	<20050704105721.Y2768@fledge.watson.org>
In-Reply-To: <20050704105721.Y2768@fledge.watson.org>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org,
	Andrew Thompson <thompsa@freebsd.org>
Subject: Re: cvs commit: src/sys/amd64/include _types.h src/sys/i386/include
 _types.h src/sys/net if_bridge.c src/sys/netinet ip_var.h       
 src/sys/netinet6 ip6_var.h
X-BeenThere: cvs-all@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: CVS commit messages for the entire tree <cvs-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-all>,
	<mailto:cvs-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-all>
List-Post: <mailto:cvs-all@freebsd.org>
List-Help: <mailto:cvs-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-all>,
	<mailto:cvs-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 04 Jul 2005 10:06:41 -0000

>> FYI, any modern ppc implementation doesn't require strict alignment 
>> for integer load/stores though there's a performance penalty for 
>> having to split the access into smaller ones. 
> 
> While it's not immediately relevant to the IP code, generally speaking, 
> is it the case that non-aligned integer reads can be non-atomic with 
> respect to other CPUs due to the multiple access implementation?

  I'd say certainly ! In fact, are there any architectures that could 
guarantee atomicity in this case ?

later,

Peter.