From owner-freebsd-stable@FreeBSD.ORG Sun Jul 6 14:35:48 2003 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9CE2237B401 for ; Sun, 6 Jul 2003 14:35:48 -0700 (PDT) Received: from alcanet.com.au (mail3.alcanet.com.au [208.178.117.11]) by mx1.FreeBSD.org (Postfix) with ESMTP id DCCD543F75 for ; Sun, 6 Jul 2003 14:35:46 -0700 (PDT) (envelope-from peter.jeremy@alcatel.com.au) Received: from sydsmtp01.alcatel.com.au (IDENT:root@localhost.localdomain [127.0.0.1])h66LZhHI005406; Mon, 7 Jul 2003 07:35:44 +1000 Received: from gsmx07.alcatel.com.au ([139.188.20.247]) by sydsmtp01.alcatel.com.au (Lotus Domino Release 5.0.12) with ESMTP id 2003070707330656:174015 ; Mon, 7 Jul 2003 07:33:06 +1000 Received: from gsmx07.alcatel.com.au (localhost [127.0.0.1]) by gsmx07.alcatel.com.au (8.12.9/8.12.9) with ESMTP id h66LZgIf001179; Mon, 7 Jul 2003 07:35:42 +1000 (EST) (envelope-from peter.jeremy@alcatel.com.au) Received: (from jeremyp@localhost) by gsmx07.alcatel.com.au (8.12.9/8.12.9/Submit) id h66LZeFE001178; Mon, 7 Jul 2003 07:35:40 +1000 (EST) (envelope-from peter.jeremy@alcatel.com.au) Date: Mon, 7 Jul 2003 07:35:40 +1000 From: Peter Jeremy To: Chuck Swiger Message-ID: <20030706213540.GU430@gsmx07.alcatel.com.au> Mail-Followup-To: Chuck Swiger , freebsd-stable@freebsd.org References: <200307051728.24681.me@farid-hajji.de> <44brw8g26e.fsf@be-well.ilk.org> <200307060029.00866.me@farid-hajji.de> <3F07576F.4030105@mac.com> Mime-Version: 1.0 In-Reply-To: <3F07576F.4030105@mac.com> User-Agent: Mutt/1.4.1i X-MIMETrack: Itemize by SMTP Server on SYDSMTP01/AlcatelAustralia(Release 5.0.12 |February 13, 2003) at 07/07/2003 07:33:06 AM,|February 13, 2003) at 07/07/2003 07:33:07 AM, Serialize complete at 07/07/2003 07:33:07 AM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline cc: freebsd-stable@freebsd.org Subject: Re: Weird vmstat -s stats X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 Jul 2003 21:35:48 -0000 On 2003-Jul-05 18:55:43 -0400, Chuck Swiger wrote: >Farid Hajji wrote: >[ ... ] >>Shouldn't such counters be at least 64 bit wide? > >You betcha. :-) The problem is that a 32-bit CPU, like the Intel x86 >family, can't increment a 64-bit counter atomicly. This isn't absolutely true. You _can_ perform atomic 64-bit operations on an x86 (for x>=5), they are just extremely expensive. There are regular threads on this sort of problem and I don't believe anyone has come up with a solution that did not involve overheads that were considered unacceptable in the general case. Peter