RE: Tracing Programs

["Richard Jackson" <richardjackson@xxxxxxxxxxxxxxxxxx>]

This is a very good first-try test technique.  In most cases, you should
need no better.  An alternative would be a Pex stats run.  Descent into more
involved Pex runs (next profile then trace) might be interesting if there
was a problem.

Richard Jackson
mailto:richardjackson@richardjackson.net
http://www.richardjacksonltd.com
Voice: 1 (303) 808-8058
Fax:   1 (303) 663-4325

-|-----Original Message-----
-|From: owner-midrange-l@midrange.com
-|[mailto:owner-midrange-l@midrange.com]On Behalf Of bmorris@ca.ibm.com
-|Sent: Wednesday, October 25, 2000 3:48 PM
-|To: MIDRANGE-L@midrange.com
-|Subject: Re: Tracing Programs
-|
-|
-|
-|>Date: Wed, 25 Oct 2000 12:30:18 -0700
-|>From: Chris Bipes <chris.bipes@cross-check.com>
-|>
-|>I have a current string parsing routine that loops thru an array.  I have
-|>rewritten it to use the C function StrTok.  What I want to do is see if
-|this
-|>is really faster than the old loop.  I can also use the scan and substr
-|BIFs
-|>to achieve the same results.  Since this is a major time critical
-|>application I want to use the most efficient way possible.  I do not have
-|a
-|>dedicated machine to test on so using job timing does not work.  How can
-|one
-|>trace the CPU time used for each transaction?  I have seen machine traces
-|>before that showed the machine instruction trace of a job.  Where do I
-|find
-|>this?  I am on V4R4.
-|
-|Chris, even without a dedicated machine, you should be able to test this.
-|Create two programs each containing just the two versions of the
-|code, in a
-|loop (make sure the code within the loop is just what's needed to do the
-|tasks
-|being compared - no unnecessary calls etc).  Have the loop iterate enough
-|times for the program to run at least 5 minutes.  For this type of program
-|I always pass the number of times in as a parameter (a perfect use for a
-|15,5
-|parm :).
-|
-|To reduce the effect of other jobs, run the programs alternately 3 or 4
-|times.
-|Don't be tempted to take an average of the times taken for each case;
-|instead
-|you should compare the best times for each case.  (If the times vary
-|wildly,
-|you're right and I'm wrong and you'll have to find another way ...)
-|
-|To increase your satisfaction that your tests are accurate, try doing the
-|tests like this (assuming 10000 lets your programs run at least a
-|couple of
-|minutes):
-|  call pgma  10000
-|  call pgmb  10000
-|  call pgma  50000
-|  call pgmb  50000
-|  call pgma 100000
-|  call pgmb 100000
-|
-|If pgma's times are x 5x and 10x and pgmb's times are y 5y and 10y, then
-|you
-|can be quite sure that it's reasonable to compare x and y.
-|
-|Barbara Morris
-|
-|
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