Period measurement

[Adi Sudewa <dewa@students.if.itb.ac.id>]

Hi,

Suppose I have this procedure :

	void do_it()
	{
		complex_calculation();
		other_complex_calculation();
	}

and this highest priority rtl thread(ignore syntax errors):
	
	pthread_make_periodic(PERIOD);
	while (1) {
		do_it();
		pthread_wait();		
	}

And my questions :
(1) I assume if execution time do_it() is greater than PERIOD, 
   then all the CPU time will be used by this thread and no other
   task have chance to run. Is it correct ?
(2) How to measure the worst-case execution time of do_it() ?
   Can I just run it 100 times, do measurement,  and pick the greatest
value ?
 
Thanks in advance,

Adi Sudewa
-
Teknik Informatika
Institut Teknologi Bandung
Indonesia