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From: Peter Boncz <p DOT boncz AT datadistilleries DOT com>
To: "'cygwin AT cygwin DOT com'" <cygwin AT cygwin DOT com>
Subject: RE: Memory problem
Date: Wed, 28 Feb 2001 18:12:25 +0100
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Christopher,

My statement is about NT vs Unix, and has nothing to do with Cygwin (or its
sbrk implementation).

This is just me speaking out of experience with the exacltly the same
(memory hungry) application on NT and on various Unixes. My experience is
that the VirtualAlloc() implementation in NT is more prone to fragmentation
on the long run than e.g. mmap() on Solaris and AIX. Just think that a
request for a 450MB array can be impeded by just 4 small blocks of used
virtual memory in awkward places. 

Virtual memory in a 32-bits address space is becoming a limiting resource,
and applications that push the envelope are sometimes bumping their nose
these days.  That's what all the 64-bits CPU/OS fuss is about.

Peter

-----Original Message-----
From: Christopher Faylor [mailto:cgf AT redhat DOT com]
Sent: Wednesday, February 28, 2001 5:10 PM
To: cygwin AT cygwin DOT com
Subject: Re: Memory problem


On Wed, Feb 28, 2001 at 12:26:56PM +0100, Peter Boncz wrote:
>Hi Tony,
>
>NT is a bit more vulnerable regarding memory fragmentation than most
Unixes.
>If you want 450MB in one big array, it may happen that the memory space has
>become so fragmented, there is no 450MB slot available anymore in the 2GB
or
>virtual memory space that you have at your disposition.

Huh?  No.  Cygwin implements the standard unix sbrk() mechanism.  I don't
know
why anything that is NT-specific would enter into this.

cgf

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