- DATA (WCRT = 175) cannot met its deadline (=125)
- DATA is released at time=250 and completes at time=425
- DATA is delayed because the semaphore is hold by
FORECAST at DATA release time (time 250)
- But at time 250, FORECAST is preempted by middle priority tasks 
such as VIDEO and RADIO (preemption by SCHED_BUS is a normal
behavior).

- priority inversion stands between time 275 and 325
 
- By activating PCP, VIDEO and RADIO do not delayed
FORECAST anymore, which permits DATA to meet its deadline