[Coco] Kernel activity on the O-Scope

[richec]

On Thursday 04 March 2010 05:24:49 pm Boisy G. Pitre wrote:
> I know posting attachments are discouraged, but in this case I hope folks
>  don't mind.
> 
> Working on my thesis here at school gives me the opportunity to play with
>  some nice test equipment.  While doing some other measurements, I figured
>  I would measure the percentage of the time NitrOS-9 runs when there is no
>  process active.  Keep in mind that every 16.67ms the clock interrupt kicks
>  in and the code in clock.asm checks interrupts, just to the kernel so it
>  can do its housekeeping (checks the queues, etc.), then inserts the active
>  process into the queue, or in this case, call the CWAI instruction since
>  there is no active process.  The shell prompt was sitting there as I
>  captured this.
> 
>  The graph below shows the amps in yellow, the volts in green and the LIC
>  line in purple.   The little peaks represent the clock/kernel activity...
>  the measured time is 700us, or .7ms.
> 
> Doing the math,  .7/16.67 * 100= 4.2%.  So 4.2% of the clock period is
>  spent in the kernel.
> 
Oooo wow... pretty colors... 8-)_ <doing my best Homer Simpson> You are indeed 
blessed to be able to experiment with and to use such equipment. Even more so 
because you know what it all means. I probably would have enjoyed learning 
that if I had taken the opportunity to do so. BUT I choose a different path.