Re: Calculating processor usage (M68K)

On 25 Nov 2003 01:34:23 -0800, [EMAIL PROTECTED] (test) wrote:

>Could someone tell me know how to calculate MIPS being used by an
>existing application, on an existing processor?
>
>I'm not looking for raw processor power available (so benchmark pgms
>won't do). We have an application (real-time, infinte loop) running on
>the processor, and want to know how busy the processor is on an
>average. It would suffice even if we could only determine the
>worst-case utilization. The application runs on pSOS on M68K.

I assume that you have development capability on the existing
application and are not trying to anaylze a "black box".  The
distinction between doing effective work and spinning in an idle loop
is one that can only be made by knowing the application code itself.
You will need to find where the processor is when it is "idle".  Then,
make a temporary modification to the code to leave some evidence of
the time that is spent in idle.  That can be either hardware or
software.  In software, you might sample a high-speed clock on entry
and exit from the idle code and accumulate the time spent in some
counters that are eventually reported out.  In hardware, you might set
a digital output to indicate idle vs. non-idle, then monitor that bit
with a scope and estimate the duty-cycle, or low-pass filter it and
measure the average voltage with a voltmeter.


-Robert Scott
 Ypsilanti, Michigan
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