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=AWL,SUBJECT_EXCESS_QP 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 6B3C1BBAF for ; Wed, 28 May 2008 14:21:52 +0200 (CEST) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AtkBAM7qPEjUnw6Db2dsb2JhbACCM5AHAQwFAgQHEwMTm2Q X-IronPort-AV: E=Sophos;i="4.27,555,1204498800"; d="scan'208";a="13144650" Received: from pih-relay04.plus.net ([212.159.14.131]) by mail3-smtp-sop.national.inria.fr with ESMTP; 28 May 2008 14:21:51 +0200 Received: from [80.229.56.224] (helo=beast.local) by pih-relay04.plus.net with esmtp (Exim) id 1K1Kf9-0005sR-20 for caml-list@yquem.inria.fr; Wed, 28 May 2008 13:21:51 +0100 From: Jon Harrop Organization: Flying Frog Consultancy Ltd. To: caml-list@yquem.inria.fr Subject: Re: [Caml-list] Re: Where's my non-classical =?iso-8859-1?q?shared=09memory=09concurrency?= technology? Date: Wed, 28 May 2008 13:16:54 +0100 User-Agent: KMail/1.9.9 References: <483BD594.7050504@doc.ic.ac.uk> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200805281316.54628.jon@ffconsultancy.com> X-Plusnet-Relay: 2e4181fd4678506ac6f027d76e706d8f X-Spam: no; 0.00; damien:01 broadcasting:98 frog:98 doligez:01 wrote:01 wrote:01 caml-list:01 concurrency:04 concurrency:04 passing:05 barrier:05 shared:06 shared:06 channel:06 channel:06 On Wednesday 28 May 2008 12:18:37 Damien Doligez wrote: > On 2008-05-27, at 11:34, Martin Berger wrote: > >>> Here I disagree. Shared memory concurrency is a specific form > >>> of message passing: Writing to a memory cell is in fact sending > >>> a message to that cell carrying two items, the new value and a > >>> return channel that is used to inform the writer that sending > >>> has succeeded, and likewise for reading. > > [...] > > > 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. Very expensive compared to what? -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. http://www.ffconsultancy.com/products/?e