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From: "Dave Korn" <dk AT artimi DOT com>
To: <cygwin AT cygwin DOT com>
Subject: RE: question about shared memory in the cygwin daemon
Date: Wed, 4 Aug 2004 18:36:55 +0100
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X-OriginalArrivalTime: 04 Aug 2004 17:36:55.0765 (UTC) FILETIME=[A2E9D050:01C47A49]

> -----Original Message-----
> From: cygwin-owner On Behalf Of Clarke, Trevor
> Sent: 04 August 2004 17:54

> I'm currently developing image processing software which will 
> use matlab
> as a "plugin" for interactive processing. The problem is, matlab, when
> called from another program, spawns a separate matlab engine process.
> The data we are working with can get very large (4gb+) so we 
> can't pass
> copies of it around. We are looking at using cygwin's shared memory
> functionality to get around this on windows (NT derivatives only).

  Your data won't even fit into a 32-bit address space, so I don't think
shared memory is going to help you.

  Even if you're using an x86-64 platform, you have to bear in mind that
you've got a virtual memory system there.  If your data set is 4Gb, and your
system RAM is < 4Gb, then even mapping it into shared memory between
processes will involve it going out to disk and back when the pagefile
starts swapping.

  Is there not a library version of matlab you can link to your application
and call into from the same process space?


    cheers, 
      DaveK
-- 
Can't think of a witty .sigline today....


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