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From: Richard Jones <rich@annexia.org>
To: Jonathan Roewen <jonathan.roewen@gmail.com>
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Pre-emptive multitasking
Date: Sun, 12 Jun 2005 11:13:23 +0100	[thread overview]
Message-ID: <20050612101323.GA21947@furbychan.cocan.org> (raw)
In-Reply-To: <ad8cfe7e0506111351671ba8c5@mail.gmail.com>

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
communication.

Rich.

-- 
Richard Jones, CTO Merjis Ltd.
Merjis - web marketing and technology - http://merjis.com
Team Notepad - intranets and extranets for business - http://team-notepad.com


  reply	other threads:[~2005-06-12 10:07 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-06-11 20:51 Jonathan Roewen
2005-06-12 10:13 ` Richard Jones [this message]
2005-06-12 22:02   ` Jonathan Roewen
2005-06-13  8:30     ` Benjamin Geer
2005-06-13 22:12       ` Jonathan Roewen

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