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[Caml-list] Pre-emptive multitasking
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Date: 2005-06-12 (10:07)
From: Richard Jones <rich@a...>
Subject: Re: [Caml-list] Pre-emptive multitasking
On Sun, Jun 12, 2005 at 08:51:44AM +1200, Jonathan Roewen wrote:
> Does the OCaml runtime support true pre-emptive multitasking with the
> systhreads module? Am curious how this works with the GC without
> breaking anything.

The GC isn't thread-safe.  This means that when OCaml code runs, it
must be protected by a global mutex.  If you have two threads running
OCaml code, they will contend for this mutex, and run (around) 50% of
the time each.  If you have two CPUs you won't gain any benefit.  The
standard solution would be to run one OCaml thread and lots of C
threads, or else use fork(2) to create one separate process for each
processor and use shared memory, sockets, pipes, etc. for


Richard Jones, CTO Merjis Ltd.
Merjis - web marketing and technology - http://merjis.com
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