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 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 20B1DBBC1 for ; Mon, 21 Apr 2008 22:47:23 +0200 (CEST) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AuMAACKaDEhQRFuwiGdsb2JhbACRUwEBAQ8mmH4 X-IronPort-AV: E=Sophos;i="4.25,691,1199660400"; d="scan'208";a="11737876" Received: from furbychan.cocan.org ([80.68.91.176]) by mail3-smtp-sop.national.inria.fr with ESMTP; 21 Apr 2008 22:47:22 +0200 Received: from rich by furbychan.cocan.org with local (Exim 4.63) (envelope-from ) id 1Jo2v3-00033y-ND; Mon, 21 Apr 2008 21:47:21 +0100 Date: Mon, 21 Apr 2008 21:47:21 +0100 To: Jon Harrop Cc: caml-list@yquem.inria.fr Subject: Re: [Caml-list] The closing gap (warning: long, inflammatory rant) Message-ID: <20080421204721.GA11434@annexia.org> References: <20080421131151.GA16777@annexia.org> <200804211544.08897.jon@ffconsultancy.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200804211544.08897.jon@ffconsultancy.com> User-Agent: Mutt/1.5.13 (2006-08-11) From: Richard Jones X-Spam: no; 0.00; 0100,:01 niches:01 ocaml:01 threads:01 garbage:01 garbage:01 wrote:01 wrote:01 typing:01 caml-list:01 lazy:02 lazy:02 data:02 argument:02 deallocate:03 On Mon, Apr 21, 2008 at 03:44:08PM +0100, Jon Harrop wrote: > On Monday 21 April 2008 14:11:51 Richard Jones wrote: > > Your threaded code is going to look really stupid when you have NUMA > > machines with dozens of cores. Why are we optimizing for a case (SMP) > > which will only be around for a few years. Arguably SMP isn't even > > around now ... the AMD machine on which I'm typing this is firmly NUMA > > with a good 10% penalty for accessing memory owned by the other > > socket. > > 10% is nothing compared to the orders of magnitude cost of message passing. Or you could use shared memory (as I said below). How do you think shared memory works in a NUMA machine anyway? > > > A concurrent GC should be developed. But I think you can compete in > > > some "niches" without a concurrent GC. > > > > Why should a concurrent GC be developed? Threaded code is a nightmare > > to write & debug, and it's only convenient for lazy programmers who > > can't be bothered to think in advance about how they want to share > > data. OCaml supports fork, event channels & shared memory right now > > (and has done for years) so there is no penalty to writing it > > properly. > > Ten years ago that was: > > "Why should we use gargage collection? Garbage collectors are a nightmare to > implement and debug and are only useful for lazy programmers who cannot be > bothered to deallocate values themselves. C++ has reference counting right > now and there is no penalty for using it properly." Thanks for the straw man argument there. Garbage collectors and _not_ using threads both improve the safety of the language. Rich. -- Richard Jones Red Hat