From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id AAA17319; Fri, 21 Feb 2003 00:11:03 +0100 (MET) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id AAA17755 for ; Fri, 21 Feb 2003 00:11:02 +0100 (MET) Received: from xanadu.ece.ucsb.edu (xanadu.ece.ucsb.edu [128.111.56.51]) by nez-perce.inria.fr (8.11.1/8.11.1) with ESMTP id h1KNB1H25993 for ; Fri, 21 Feb 2003 00:11:01 +0100 (MET) Received: from ece.ucsb.edu (gimli.ece.ucsb.edu [128.111.56.252]) by xanadu.ece.ucsb.edu (8.12.2/8.12.2) with ESMTP id h1KNAxPr007929 for ; Thu, 20 Feb 2003 15:10:59 -0800 (PST) Date: Thu, 20 Feb 2003 15:10:35 -0800 Mime-Version: 1.0 (Apple Message framework v551) Content-Type: text/plain; charset=US-ASCII; format=flowed Subject: Re: [Caml-list] native threads not parallel? From: Shivkumar Chandrasekaran To: caml-list@inria.fr Content-Transfer-Encoding: 7bit Message-Id: <847A10BA-4528-11D7-8C93-000393942C76@ece.ucsb.edu> X-Mailer: Apple Mail (2.551) Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk Not sure if this issue from an earlier discussion was fully resolved or not. But I seem to have the same problem as discussed by Markus Mottl (see attachment below) on Mac OS X 10.2.4 on a dual processor G4 machine. An earlier message in that thread mentioned that there was no such problem on dual-processor Linux machines. I have two questions: 1. Has anybody else figured out how to get parallelism using native threads on Mac OS X? 2. Will I get the parallelism if I switch to LinuxPPC? Thanks, --shiv-- PS: Does ocaml work properly on LinuxPPC? > Re: [Caml-list] native threads not parallel? > To :Xavier Leroy < Xavier.Leroy@inria.fr > > Subject :Re: [Caml-list] native threads not parallel? > From :Markus Mottl < mottl@miss.wu-wien.ac.at > > Date: Thu, 21 Jun 2001 15:43:16 +0200 > Cc: OCAML < caml-list@inria.fr > > Content-Disposition: inline > In-Reply-To: < 20010615233325.B24915@miss.wu-wien.ac.at >; from > mottl@miss.wu-wien.ac.at on Fri, Jun 15, 2001 at 23:33:26 +0200 > References: < 20010615184931.A25835@miss.wu-wien.ac.at > < > 20010615191046.A20258@pauillac.inria.fr > < > 20010615204218.C25835@miss.wu-wien.ac.at > < > 20010615233325.B24915@miss.wu-wien.ac.at > > User-Agent: Mutt/1.2.5i > On Fri, 15 Jun 2001, Markus Mottl wrote: > > I have just been told that things work smoothly with dual-processor > > machines under Linux, and it also turned out due to more > experimentation > > that the behaviour of native threads under Solaris is comparable to > > a lottery: when running very long, it seems that multiple threads are > > used. Sometimes. But sometimes you can also get bus errors. It's > really > > unpredictable. Better don't bother with native threads under > Solaris... > > I couldn't resist and have done another test now. First, I have made > sure that multiple threads work under C. As Xavier has pointed out, > this > requires setting the concurrency level to more than the default of 1. > Works fine (= in parallel). > > Then I have written a small test program that tries to do the same > under > OCaml - but no success... > > Here are the the timings achieved by calling C via OCaml: > > Running sequentially: > Wall clock time: 6.598713 > > Running in parallel: > Wall clock time: 6.601169 > > > Here are the the timings achieved by using C only (clearly runs faster > with threads): > > Running sequentially > Wall clock time: 6.995337 > > Running in parallel > Wall clock time: 3.910411 > > The only thing I can imagine is that OCaml somehow changes > scheduling so that the threads cannot run in parallel anymore, even if > "enter_blocking_section" is used. Is this possible? Or am I just making > some stupid mistake? > > Regards, > Markus Mottl --shiv-- ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners