Re: [Caml-list] Concurrent/parallel programming

[Francois Berenger <berenger@riken.jp>]

On 01/08/2014 11:35 AM, Yotam Barnoy wrote:
> Thanks for the links and info, everyone.
>
> Gerd, would it be possible to put netmulticore up on opam?

I think it should be included in the ocamlnet package that is in OPAM.

> I realize
> this is a sensitive topic for you, but from what I can tell, this is the
> most comprehensive and efficient solution to parallel programming that
> exists for ocaml, so why not make it as easily available as possible?
>
> Also, regarding the ocaml_modify() and ocaml_initialize() regression in
> 4.01 -- yikes! Is there any way to get support back for writing outside
> of the ocaml heap? This seems like a pretty big deal! (Sorry if I'm
> arriving late for whatever discussion took place about this before).
>
> -Yotam
>
>
> On Tue, Jan 7, 2014 at 3:35 PM, Gerd Stolpmann <info@gerd-stolpmann.de
> <mailto:info@gerd-stolpmann.de>> wrote:
>
>     There is Netmulticore, a part of Ocamlnet:
>
>     http://projects.camlcity.org/projects/dl/ocamlnet-3.7.3/doc/html-main/Intro.html#ch_comp
>
>     It utilizes shared memory, and accesses it from several processes. There
>     is no C code involved, but it is fairly unsafe nevertheless, because you
>     need to stick to certain programming rules, or the program crashes.
>     However, if you manage to encapsulate all the unsafe things, it is a
>     good option. I'm using Netmulticore in the Plasma Map/Reduce
>     implementation.
>
>     Gerd
>
>     Am Dienstag, den 07.01.2014, 14:54 -0500 schrieb Yotam Barnoy:
>      > Hi List
>      >
>      >
>      > So far, I've been programming in ocaml using only sequential
>     programs.
>      > In my last project, which was an implementation of a large machine
>      > learning algorithm, I tried to speed up computation using a
>     little bit
>      > of parallelism with ParMap, and it was a complete failure. It's
>      > possible that more time would have yielded better results, but I just
>      > didn't have the time to invest in it given how bad the initial
>     results
>      > were.
>      >
>      >
>      > My question is, what are the options right now as far as parallelism
>      > is concerned? I'm not talking about cooperative multitasking, but
>      > about really taking advantage of multiple cores. I'm well aware
>     of the
>      > runtime lock and I'm ok with message passing between processes or a
>      > shared area in memory, but I'd rather have something more high level
>      > than starting up several processes, creating a named pipe or a
>     socket,
>      > and trying to pass messages through that. Also, I assume that using a
>      > shared area in memory involves some C code? Am I wrong about that?
>      >
>      >
>      > I was expecting Core's Async to fill this role, but realworldocaml is
>      > fuzzy on this topic, apparently preferring to dwell on cooperative
>      > multitasking (which is fine but not what I'm looking for), and I
>      > couldn't find any other documentation that was clearer.
>      >
>      >
>      > Thanks
>      >
>      > Yotam
>      >
>
>     --
>     ------------------------------------------------------------
>     Gerd Stolpmann, Darmstadt, Germany gerd@gerd-stolpmann.de
>     <mailto:gerd@gerd-stolpmann.de>
>     My OCaml site: http://www.camlcity.org
>     Contact details: http://www.camlcity.org/contact.html
>     Company homepage: http://www.gerd-stolpmann.de
>     ------------------------------------------------------------
>
>


-- 
Best regards,
Francois Berenger.