Re: GNU Make performance question

[Larry Hall <cygwin-lh at cygwin dot com>]

At 10:09 PM 3/23/2004, you wrote:
>I am writing a document on the performance of gnu make and various
>makefiles and came across something I can't explain.
>
>To measure the speed of gnu make $(subst...) versus sed I wrote this
>simple makefile:
>
>  p1000 := ...<1000 character string with periodic semicolons>...
>  # This simple assignment 10000 times.
>  x := $(subst ;, ,$(p1000))
>  ...
>
>I then run this makefile 10 times and average the times.  I ran the
>makefile on Windows XP with Cygwin and a Linux system with RedHat 9:
>
>  Windows XP     1.8 GHz/P4/512MB   82644 assignments / second
>  Linux     450 MHz/P2/256MB    111111 assignments / second
>
>As you can see the puny 450 MHz P2 managed to kick Windows ass.  I'm
>at a total loss to explain why, though.  For instance,
>
>* Both systems were idle, with no memory hogging apps running (the
>  Windows machine was freshly booted)
>
>* The test runs the makefile only 10 times, for only 10 process
>  create/loads and 100000 assignments
>
>* The test seems to be entirely cpu bound, with both executables
>  compiled by gcc (albeit different versions)
>
>Could this be entirely explained by the difference in process creation
>times?  I would have thought that the 4 times clock rate and beefier
>ram would have adequately compensated.
>
>Note, this is not - in any way - a complaint about performance.  I'd
>just like to understand the reasons.


Some of it, at least, is likely the overhead of Cygwin.  You might want to 
try a completely native version for Windows if you're looking for a more
direct comparison.



--
Larry Hall                              http://www.rfk.com
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
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