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Re: Does Cygwin have a 2GB Memory/RAM limit ?





I am running a Java application (Java version 1.4.x).

I try to allocate a JVM with anything much larger than 1.6GB and it fails.
So I started to look at memory (1.6GB is no problem for Java to allocate
providing everything else is working OK).

Two of the places I looked (see below) are the top command and vmstat.
Both of which reported 2GB of RAM available despite my having set max
memory size to 4GB.

Based on that observation, I assumed that cygwin has a built in memory
limit of 2GB.
I'm wondering if anyone has seen this before, or has an environment (RAM >
2GB) where they could do a quick test to see if setting the max memory to >
2GB(see html link below)  reports only 2GB available.

I've checked the FAQ, searched the news groups, googled 'till I can't
google no more ;-).  Can't find any reference to this.

Thanks for any help.

Dan Nazario





                                                                                                                                  
                                                                                                                                  
                        "Timothy C                                                                                                
                        Prince"                To:       dan_nazario@americancentury.com                                          
                        <tprince@myreal        cc:       cygwin@cygwin.com                                                        
                        box.com>               Subject:  Re: Does Cygwin have a 2GB Memory/RAM limit ?                            
                                                                                                                                  
                        Sent by:                                                                                                  
                        cygwin-owner@cy                                                                                           
                        gwin.com                                                                                                  
                                                                                                                                  
                                                                                                                                  
                        10/29/2003                                                                                                
                        06:29 PM                                                                                                  
                                                                                                                                  
                                                                                                                                  
                                                                                                                                  
                                                                                                                                  
                                                                                                                                  




I don't think you've defined your problem well enough to answer.  Are you
running a single thread gcc program which mallocs memory until it fails?
If you have multiple CPUs and run multiple threads or multiple instances of
your program, you might be able to use more of the memory.

-----Original Message-----
From: Dan_Nazario/ACIM/americancentury@americancentury.com
To: cygwin@cygwin.com
Date: Wed, 29 Oct 2003 17:40:02 -0600
Subject: Does Cygwin have a 2GB Memory/RAM limit ?

I am trying to run cygwin on a Windows 2003 server with 8GB of ram.

I have set the registry key to inform cygwin the max memory should be 4096
(4GB).  Checking the registry - I see the value is set to 4096.
(see: http://www.cygwin.com/cygwin-ug-net/setup-maxmem.html)
In spite of this, all indications are that it does not see more than 2GB
(2097151K) of RAM.  (top and vmstat output)

Can anyone else confirm this - that memory above 2GB is not visible to
cygwin.  Any known work-arounds?

Thanks in advance.

Dan Nazario

P.S.   Cygwin uname info is: CYGWIN_NT-5.2 **server name **
1.5.3(0.90/3/2) 2003-09-01 13:15 i686 unknown unknown Cygwin

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Tim Prince

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