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 Received: from mail1-relais-roc.national.inria.fr (mail1-relais-roc.national.inria.fr [192.134.164.82]) by yquem.inria.fr (Postfix) with ESMTP id 26673BC69 for ; Tue, 4 Dec 2007 17:25:23 +0100 (CET) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgAAAHgNVUc+FFrDh2dsb2JhbACPTgEBCAop X-IronPort-AV: E=Sophos;i="4.23,249,1194217200"; d="scan'208";a="5252250" Received: from dns.vtab.com (HELO oden.vtab.com) ([62.20.90.195]) by mail1-smtp-roc.national.inria.fr with ESMTP; 04 Dec 2007 17:25:22 +0100 Received: from oden.vtab.com (oden.vtab.com [127.0.0.1]) by oden.vtab.com (Postfix) with ESMTP id DE3B726EEE9; Tue, 4 Dec 2007 17:25:21 +0100 (CET) Received: from kicki.hq.vtech (kicki.hq.vtech [10.0.0.211]) by oden.vtab.com (Postfix) with ESMTP id C642626EEE3; Tue, 4 Dec 2007 17:25:21 +0100 (CET) Received: by kicki.hq.vtech (Postfix, from userid 7557) id BFE245401E; Tue, 4 Dec 2007 17:25:21 +0100 (CET) From: "=?utf-8?b?TWF0dGlhcyBFbmdkZWfDpQ==?= =?utf-8?b?cmQ=?=" To: basile@starynkevitch.net Cc: Christophe.Raffalli@univ-savoie.fr, caml-list@yquem.inria.fr In-reply-to: <47556617.7020602@starynkevitch.net> (message from Basile STARYNKEVITCH on Tue, 04 Dec 2007 15:37:11 +0100) Subject: Re: [Caml-list] minithread (was OCaml on Sony PS3) References: <875c7e070709060755r1d0d099ds30a25ea78d0fd85a@mail.gmail.com> <46E01A27.1070207@janestcapital.com> <509223F0BF55E74FA1247D17207E7A0C01D75893@orsmsx419.amr.corp.intel.com> <87r6lb90tw.fsf@linux-france.org> <46E046DF.5010103@univ-savoie.fr> <46E04B85.1020004@naughtydog.com> <13858952.post@talk.nabble.com> <47528593.9060106@inria.fr> <14116972.post@talk.nabble.com> <200712021419.01821.konrad@tylerc.org> <14121946.post@talk.nabble.com> <4754643A.6020503@univ-savoie.fr> <47556617.7020602@starynkevitch.net> Message-Id: <20071204162521.BFE245401E@kicki.hq.vtech> Date: Tue, 4 Dec 2007 17:25:21 +0100 (CET) X-Virus-Scanned: ClamAV using ClamSMTP X-Spam: no; 0.00; mattias:01 mattias:01 ocaml:01 ocaml:01 computations:01 chunks:01 computations:01 sony:98 garbage:01 heap:01 caml-list:01 data:02 data:02 implemented:02 perhaps:05 >However, (one of the) the CELL coprocessor -eg SPU) might be used to >implemented Ocaml garbage collector. > >A copying GC has to move quite a lot of data, and it could be possible >that CELL's coprocessors could be useful for that (assuming that they >access memory as quickly as the processor). They don't so it isn't, and doing GC by a coprocessor that cannot directly access the memory it manages does not sound very practical. The PPE has the memories of all SPUs mapped into its physical address space, so it could possibly do the GC for them. But again, given the limited amount of SPU-private memory, it would probably not be a useful approach. Better use of the SPUs would be to run computations that can use manual memory management (perhaps not using a heap at all), operating on small chunks of data at a time. Such computations could be described in a simpler language that is more amenable to parallelisation. >I still think that SPU on PS3 are only useful for games, or specialized >(e.g. graphical) applications. Maybe, but there are cell blades with more reasonable amounts of memory, and for experimentation regarding how to use the processor, a PS3 goes quite far and is very economical. Ground-breaking science has been made in less than 256 MB.