From owner-freebsd-amd64@FreeBSD.ORG  Fri Feb  4 22:12:29 2005
Return-Path: <owner-freebsd-amd64@FreeBSD.ORG>
Delivered-To: freebsd-amd64@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id CC7F616A580
	for <amd64@FreeBSD.org>; Fri,  4 Feb 2005 22:12:27 +0000 (GMT)
Received: from mail21.sea5.speakeasy.net (mail21.sea5.speakeasy.net
	[69.17.117.23])	by mx1.FreeBSD.org (Postfix) with ESMTP id C710E43D45
	for <amd64@FreeBSD.org>; Fri,  4 Feb 2005 22:12:26 +0000 (GMT)
	(envelope-from jhb@FreeBSD.org)
Received: (qmail 26091 invoked from network); 4 Feb 2005 22:12:26 -0000
Received: from server.baldwin.cx ([216.27.160.63])
	(envelope-sender <jhb@FreeBSD.org>)AES256-SHA encrypted SMTP
	for <peter@FreeBSD.org>; 4 Feb 2005 22:12:26 -0000
Received: from [10.50.40.202] (gw1.twc.weather.com [216.133.140.1])
	(authenticated bits=0)
	by server.baldwin.cx (8.13.1/8.13.1) with ESMTP id j14MCGNK065270;
	Fri, 4 Feb 2005 17:12:21 -0500 (EST)
	(envelope-from jhb@FreeBSD.org)
From: John Baldwin <jhb@FreeBSD.org>
To: amd64@FreeBSD.org
Date: Fri, 4 Feb 2005 15:58:28 -0500
User-Agent: KMail/1.6.2
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
  charset="us-ascii"
Content-Transfer-Encoding: 7bit
Message-Id: <200502041558.28521.jhb@FreeBSD.org>
X-Spam-Status: No, score=-102.8 required=4.2 tests=ALL_TRUSTED,
	USER_IN_WHITELIST autolearn=failed version=3.0.2
X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on server.baldwin.cx
cc: peter@FreeBSD.org
Subject: [PATCH] Change atomic operations to use fences for memory barriers
X-BeenThere: freebsd-amd64@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Porting FreeBSD to the AMD64 platform <freebsd-amd64.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-amd64>,
	<mailto:freebsd-amd64-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-amd64>
List-Post: <mailto:freebsd-amd64@freebsd.org>
List-Help: <mailto:freebsd-amd64-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-amd64>,
	<mailto:freebsd-amd64-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 04 Feb 2005 22:12:29 -0000

The patch below changes the atomic operations on amd64 to use the cheaper 
fence instructions for memory barriers.  I'd like people to test it to see if 
1) it breaks things or not, and 2) if it impacts performance either in a good 
way or a bad way.  For this last I'm curious about both UP and SMP as my 
initial guess is that it will help on UP but might hurt on SMP.

-- 
John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org