Listing 3: (a) RTLinux interrupt latency pseudocode; (b) RTLinux interrupt latency output.

(a)
ISR
   if (start) {
   ticks = rtl_getticks() - start;
   if (ticks > worst)
      worst = ticks;
   }
   start = rtl_getticks();
   rtl_settimer(period);
main()
   ....
   intr_latency = ((worst period) * NSECS_PER_SEC) / rtl_clock_tick_rate;

(b)
Interrupt Latency: (96h 0m 0s test)
39.6 us