Re: [Caml-list] Efficient OCaml multicore -- roadmap?

[Hugo Ferreira <hmf@inescporto.pt>]

On 04/19/2011 10:57 AM, Eray Ozkural wrote:
>
>
> On Fri, Mar 25, 2011 at 9:19 PM, Hugo Ferreira <hmf@inescporto.pt
> <mailto:hmf@inescporto.pt>> wrote:
>
>     On 03/25/2011 06:24 PM, Martin Jambon wrote:
>
>             On 03/25/2011 01:10 PM, Fabrice Le Fessant wrote:
>
>                    Of course, sharing structured mutable data between
>                 threads will not be
>                 possible, but actually, it is a good thing if you want
>                 to write correct
>                 programs ;-)
>
>
>         On 03/25/11 08:44, Hugo Ferreira replied:
>
>             I'll stick to my guns here. It simply makes solving certain
>             problem
>             unfeasible. Point in case: I work on machine learning
>             algorithms. I
>             use large data-structures that must be processed (altered)
>             in order to learn. Because these data-structures are large
>             it become
>             impractical to copy this to a process every time I start off
>             a new
>             "thread".
>
>
>         The solution would be to use get/set via a message-passing
>         interface.
>
>
>     Cannot see how this works. Say I want to share a balanced binary tree.
>     Several processes/threads each take this tree and alter it by adding and
>     deleting elements. Each (new) tree is then further processed by other
>     processes/threads.
>
>     How can get/set be used in this scenario?
>
>
> I think it won't have good performance and it won't scale, and it will
> fail for truly delicate shared memory architectures of the future with
> thousands of cores....
>
> And neither will it support on-chip message passing facilities of those
> future processors.
>
> The shared memory message passing never worked too well, anyway, too
> many redundant copies. Not fitting for high performance computing.
>
> No need at all except for embarrassingly parallel applications. I
> suppose that's the target, right?
>

Yes. The problem is decomposable and can use sampling.
The idea is to have threads that take a data-set decompose it and make
the smaller parts available for further (parallel) processing.

Regards,
HF

> Best,
>
> --
> Eray Ozkural, PhD candidate.  Comp. Sci. Dept., Bilkent University, Ankara
> http://groups.yahoo.com/group/ai-philosophy
> http://myspace.com/arizanesil http://myspace.com/malfunct
>