Re: Using large memory segments with a telnet session

[Earnie Boyd <earnie_boyd at yahoo dot com>]

"Rist, Mark J." wrote:
> 
> Thanks to the archive of this mailing list, I have discovered that you can
> use large memory segments with cygwin by modifying the registry key:
> 
> HKEY_CURRENT_USER\Software\Cygnus Solutions\Cygwin
> 
> and adding the value heap_chunk_in_mb (DWORD set to max memory amount).
> 
> The problem that I am having is that I am logged into a machine via telnet
> using
> the inetutils. It appears that the registry setting is ignored for telnet
> sessions. So
> I can't run large memory programs when logged in remotely.
> 
> The problem may be exaggerated by the fact that I am using roaming profiles
> and the registry for the user I am logging in as is stored remotely.
> 
> I have tried several things to no avail:
> 1. Setting HKLM\Software\Cygnus Solutions\Cygwin\heap_chunk_in_mb
> I thought this might work since system wide mount points seem to be working
> and these are set under HKLM. Didn't work.
> 2. Setting HKCU\Software\Cygnus Solutions\Cygwin\heap_chunk_in_mb for the
> user running the inetd service. Nope.
> 
> I am running out of ideas. I am fairly sure that I can recompile the
> cygwin1.dll and
> change the default heap size to get around this problem, but I would prefer
> to
> handle this as a configuration so that I don't have to recompile for every
> release.
> 
> Any ideas?
> 

Using the source I find:

 /* Note that reserving a huge amount of heap space does not result in
 swapping since we are not committing it. */
 /* FIXME: We should not be restricted to a fixed size heap no matter
 what the fixed size is. */

 heap_chunk_in_mb = reg.get_int ("heap_chunk_in_mb", 128);
 if (heap_chunk_in_mb < 4)
   {
     heap_chunk_in_mb = 4;
     reg.set_int ("heap_chunk_in_mb", heap_chunk_in_mb);
   }

So if your program isn't finding the registry key then the heap_chunk is
4mb not 128mb.  Also, you can see in the comments that there is no
reason for a fixed limit other than no one has patched the source yet. 
So, please, fix it and submit the patch to cygwin-patches@cygwin.com for
consideration.  You'll need to do the legal paper work with the release
forms at http://cygwin.com.

Cheers,
Earnie.

__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com

--
Want to unsubscribe from this list?
Check out: http://cygwin.com/ml/#unsubscribe-simple