Re: DJGPP vs Cygwin

["Larry Hall (RFK Partners, Inc)" <lhall at rfk dot com>]

At 10:48 PM 11/5/2002, CBFalconer wrote:
>I have been using Cygwin to check portability, and recently tried
>an experiment.  I compiled and run the same, largely compute
>bound, program on both systems and timed their execution.  Both
>were compiled with "gcc -W -Wall -O2 -ansi -pedantic -gstabs+",
>using gcc 3.1 on DJGPP, and gcc 3.2 on Cygwin.  Both on the
>identical machine, running W98.
>
>The program was considerably slower on Cygwin.  The execution
>commands were:
>
>timerun a 30000
>timerun a 10000    on DJGPP, using 4dos command processor
>                    (timerun is an alias, involving timer command)
>
>time ./a 30000
>time ./a 10000     on Cygwin, using bash 2.05
>
>I believe the majority of the Cygwin slowdown is due to the slower
>loading (although the program is much smaller than under DJGPP)
>and slower console output handling.  This is based on the
>difference in times between the shorter and longer runs.
>
>FYI the test program was:


<snip>

General performance with Cygwin is a known issue.  At least some portion
of this is the expected price you pay for POSIX compatibility.  A better
test would be to compare DJGPP with mingw (or even Cygwin gcc with 
-mno-cygwin).  Still, I don't think anyone here will be very surprised 
to hear that Cygwin versions of the same programs run slower.  If you're
curious, there's more discussion of this in the email archives.  Some of
the performance issues will be addressed over time.  Some you'll just have 
to live with.  If you're inclined to track down the performance issues you 
see and offer possible solutions, I know the list would be very interested 
in your results.

  


Larry Hall                              lhall@rfk.com
RFK Partners, Inc.                      http://www.rfk.com
838 Washington Street                   (508) 893-9779 - RFK Office
Holliston, MA 01746                     (508) 893-9889 - FAX


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