From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.1.3 X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from mail3-relais-sop.national.inria.fr (mail3-relais-sop.national.inria.fr [192.134.164.104]) by yquem.inria.fr (Postfix) with ESMTP id 50563BBAF; Wed, 28 May 2008 19:42:57 +0200 (CEST) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av4AAPo2PUjAXQImiGdsb2JhbACBVZBRAQEBDyCcUg X-IronPort-AV: E=Sophos;i="4.27,556,1204498800"; d="scan'208";a="13161290" Received: from discorde.inria.fr ([192.93.2.38]) by mail3-smtp-sop.national.inria.fr with ESMTP; 28 May 2008 19:42:42 +0200 Received: from mail1-relais-roc.national.inria.fr (mail1-relais-roc.national.inria.fr [192.134.164.82]) by discorde.inria.fr (8.13.6/8.13.6) with ESMTP id m4SHggNw011093 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=OK); Wed, 28 May 2008 19:42:42 +0200 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AlQBAFY2PUiKJV+LgWdsb2JhbACBVZBRAQEQIAWcUQ X-IronPort-AV: E=Sophos;i="4.27,556,1204498800"; d="scan'208";a="12849767" Received: from tart.dcs.qmul.ac.uk (HELO mail.dcs.qmul.ac.uk) ([138.37.95.139]) by mail1-smtp-roc.national.inria.fr with ESMTP; 28 May 2008 19:42:41 +0200 Received: from host86-136-80-11.range86-136.btcentralplus.com ([86.136.80.11] helo=xila.local) by mail.dcs.qmul.ac.uk with esmtpsa (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.68) (envelope-from ) id 1K1Pfb-0002Rm-RD; Wed, 28 May 2008 18:42:41 +0100 Message-ID: <483D9961.9040302@doc.ic.ac.uk> Date: Wed, 28 May 2008 18:41:53 +0100 From: Martin Berger User-Agent: Thunderbird 2.0.0.14 (Macintosh/20080421) MIME-Version: 1.0 To: Damien Doligez , caml-list Subject: Re: [Caml-list] Re: Where's my non-classical shared memory concurrency technology? References: <200805181735.50621.jon@ffconsultancy.com> <4831686F.8010903@doc.ic.ac.uk> <1211206144.11053.15.camel@flake.lan.gerd-stolpmann.de> <4833D7E8.8060502@doc.ic.ac.uk> <4EDC5A3B-DFD2-47EA-9C22-F0B355D7BBC7@inria.fr> <483BD594.7050504@doc.ic.ac.uk> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-DCS-Interface-Port: 465 X-DCS-Auth-User: martinb (person) X-Miltered: at discorde with ID 483D9992.000 by Joe's j-chkmail (http://j-chkmail . ensmp . fr)! X-Spam: no; 0.00; abstraction:01 model:01 abstraction:01 broadcasting:98 caml-list:01 concurrency:04 passing:05 barrier:05 shared:06 shared:06 channel:06 memory:09 memory:09 doesn't:12 moreover:13 >> But broadcasting is a form of message-passing too! > > That wasn't my point. My point was that there is no return channel. > If you want to know when your write is done, you have to use a lock > or a memory barrier. Both are very expensive. As I said, it's a matter of abstraction level. My point is: you can model both abstraction levels with message passing. Moreover, using shared memory doesn't magically make these synchronisation issues go away. They remain. Martin