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| Date: | -- (:) |
| From: | Wolfgang Lux <wlux@u...> |
| Subject: | Re: [Caml-list] OCaml and implicit parallelism (threading) |
Vasili Galchin wrote: > Hello, > > I have: http://www.csg.csail.mit.edu/Users/arvind/pub.html. OCaml > allows explicit threading through the Unix library, but are there any > plans to do use implicit parallelism (via the OCaml compilers) to do > parallel expression evaluation where possible? I can't speak for Inria, but I would not expect them to do anything in that direction. The problem is that the implicit parallelism in functional languages is usually much too fine grained. For instance, consider the expression sqr 3 + sqr 6 where sqr is defined as fun x -> x * x. The function sqr is side effect free, so in principle both multiplications could be evaluated in parallel. However, the overhead for generating new parallel threads for these computations is -- obviously -- much too high. It is a very delicate decision when to parallelize computations and most people agree that this decision is best made by the programmer. At least nobody has come up with a generic algorithm for exploiting implicit parallelism in a reasonable way (i.e., such that there is really a gain in efficiency). Regards Wolfgang