Subj : sweep
To   : Jonathan De Boyne Pollard
From : Eddy Thilleman
Date : Fri Aug 03 2001 12:40 am

Hello Jonathan,

Tuesday 31 July 2001 08:06, Jonathan de Boyne Pollard wrote to Eddy Thilleman:

ET>> This new version of sweep has the same small delays as the
ET>> previous one, so these delays might be caused by calling the
ET>> command interpreter (CMD.EXE on my system).

JdBP> Possibly, although it's always better to profile the application to
JdBP> determine this.  With a REXX script run within the command interpreter
JdBP> process, there isn't the overhead of invoking an additional instance
JdBP> of the command interpreter when one issues an external command, which
JdBP> may be why your REXX script is faster.

I don't have experience profiling with REXX. I'll look into this when I've 
time.

JdBP> You can optimise things slightly, of course.  Here are some
JdBP> suggestions:

JdBP> 1.    Change your calls to DosFind{First,Next} to grab many directory
JdBP> entries in a single call, rather than just a single one (and then have
JdBP> an inner loop that iterates over the buffer entry by entry).

Do I need to change or replace the lines with DosFindFirst() and DosFindNext() 
or should I just change the number of entries to find? Problably I need extra 
calls to DosFindFirst() and DosFindNext() to iterate over entries in the 
buffer? How would I make them work with the entries in the buffer?

JdBP> 2.    Obtain the value of the COMSPEC environment variable just
JdBP> once.

I already do this in all the versions.

JdBP> 3.    Use the API of my 32-bit CMD to invoke commands, rather than
JdBP> spawning an instance of the command interpreter as a child process.
JdBP> Commands would be interpreted by an interpreter for the CMD language
JdBP> running directly in your SWEEP process itself.

I need to study this, I haven't had the time yet (I don't know when I've the 
time).

JdBP> If the problem is the process execution overhead for the command
JdBP> interpreter, as you suspect, the third suggestion may result in the
JdBP> largest speed increase.

I'll look into it.


  Greetings   -=Eddy=-

  email: e.thilleman@freeler.nl
         e.thilleman@hccnet.nl

.... Beer Bong? Now that's a sport I can get into!
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 * Origin: "DOS for dummies?"  Isn't that what Windows is? (1:2320/38.3)

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