On Jul 12, 2008, at 5:07 AM, Elvar Ólafsson wrote:

> Hi.
>
> In case there was something wrong with my code, I decided to try  
> this out on the BlinkToRadio app that is described in the mote-to- 
> mote communication tutorial. After doing some unofficial timing of  
> the program running with 16 and 32 nodes, with the timer firing  
> every 2.500.000 milliseconds, it seems that when you double the  
> amount of nodes simulated then the real-time between firing also  
> doubles. If you double the time that the timers fire at, then the  
> real-time also doubles.
>
> This code contains no loops except the following one, which is in my  
> python script. It makes sure that simulator runs until I tell it to  
> stop.
>
> status = t.runNextEvent();
> try:
>   while(status != 0):
>     status = t.runNextEvent();
> except KeyboardInterrupt:
>   print "Simulation stopped"
>
> So I guess the simulator just becomes that slow when running with  
> 100+ nodes and making them fire every 10-15 million milliseconds.  
> Unless, I am misunderstanding something.
>
> With regards,

Oh, that make a lot more sense.

10-15 million milliseconds is 10-15,000 seconds. The atmega128 timer  
stack's slowest hardware interrupt rate is approximately 4Hz (overflow  
on an 8-bit, 1kHz counter). So each node needs to process at the very  
least 60,000 TOSSIM events per timer firing. If you are running 100  
nodes, then this is 6 million events. I didn't realize your timer  
durations were so long.

Phil
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