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Message-ID: <3A7A25FF.2A2BDB7@nc.rr.com>
Date: Thu, 01 Feb 2001 22:14:07 -0500
From: Greg Smith <gsmith AT nc DOT rr DOT com>
MIME-Version: 1.0
To: cygwin AT cygwin DOT com
Subject: Some basic questions
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Hi,

I'm a minor developer for an open source project called Hercules which emulates
IBM mainframe architecture under linux (http://www.conmicro.cx/hercules/).
Some enterprising souls have gotten the program to work under windows32 by
utilizing cygwin.  I must admit, I'm impressed with the performance of the program
running on my NT 4.0 sp6 dual pIII 256M system...

q1) The program obtains the emulated storage in a single malloc().  Under linux,
     we allow the size to range up to 256M, but under cygwin, the most storage
     we can malloc at a single time is 96M.  Is there some way we can adjust this limit ?
     By the same token, we seem to get malloc() failures a lot sooner than we do
     under linux; I am pretty sure the total amount of space we've tried to obtain is
     under 256M; again, is this some limit we can bypass ?

q2) What is the state of pthreads under cygwin ?  (The emulator is heavily multi-threaded).
     Currently we are using an implementation of pthreads from
     ftp://sources.redhat.com/pub/pthreads-win32, and using the snapshot from August 13
     (later instances seem to require a dll that I haven't been successful in creating).

q3) I am having a difficult time debugging the multi-threaded program both under
     cygwin and linux (Redhat 7.0 + the 2.4 kernel and associated requisites).  I
     assume my problems under cygwin is due to using a foreign pthreads implementation ?
     I would also be extremely grateful if some kind person could direct me to
     some instructions for debugging under linux, too.  By the way, the cygwin debugger
     is impressive, is there a linux equivalent too ?  (Afraid my ignorance is showing
     here, I'm actually a mainframer type myself).

q4) One reason I upgraded to linux kernel 2.4 is that the program works, in my
     personal experience, 20% faster under cygwin than under linux.  Even with the
     new kernel, I can not recoup the performance difference.  Does anyone have
     a plausible explanation ?

This is my first post to the list, and I've only been a member for 15 min ;-), so if
I've overstepped some boundaries then I'm sure some of you will let me know...

Thanks,

Greg Smith
gsmith at nc dot rr dot com


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