Re: "Remove Backspace" test harness

[ALTENBACH,CHRISTIAN <cal...@uc...>]

> can just pick up were we left off and everyone can get up to speed on 
> the issues without too much effort.


I see several issues that must be discussed.

(1) A good set of test strings.
===============================
I would think that in real life such a VI typically encounters relatively
short inputs with only a few \b characters. (In this respect, the current
test string is quite pathological).

A VI needs to be fast under all kinds of inputs and should not encounter
slowdowns under certain conditions, so I suggest the following set of
strings (to be expanded as needed):
- an empty string
- A short string (currently I use
"XX\b\b\b\bAAAA\b\b\bBCC\bDXXX\b\b\b"=ABCD)
- Jim's long string
- A string of 1000000 characters (no \b!)
- A string of 1000000 \b characters
- A string of 1000000 characters, all even numbered characters are "\b".

Suggestion for scoring:
The times for each string are normalized to the fastest time (e.g. if one
candidate is 10% slower, it would get a 1.1). Winner will have lowest
average score, which could be as low as 1 if it is fastest on all strings
(unlikely?).

(2) VI settings
===============
I am not sure if we should force priorities/reentrant on the VIs as
currently done, but if so, what should the settings be?

(3) VI execution
================
There are several ways to execute the VIs. Jim uses "invoke node" while my
current VI uses "call by reference node". Jim sets the actual VI to "time
critical", I set the core tester VI to "time critical", while setting the
test subject to subroutine.

What is better and why? What more realistically models the use in a real
application?

(4) Timing
==========
Due to the ms timer resolution, the test must last at least a few hundred ms
to get a few significant digits. Fast running VIs need to be called inside
a loop, with the loop count tuned to the execution time.
I would not use any averaging of runs, but do multiple runs, then pick the
fastest. (All OS disturbances tend to lengthen the time!) 


'later
Christian