This is from the William Stalling Book 9th Edition Operatiing Systems

Problems 3.1. A system adopts a priority-based preemptive scheduling where the initial priority of a process increases by 1 after every 5 ms. In a recorded time span, the system has four processes, P1, P2, P3 and P4, as shown in the following table: PROCESS INITIAL ARRIVAL TIME TOTAL CPU TIME IN MS ID P P2 P3 P4 PRIORITY IN MS 0 15 7.5 10 15 10 Draw a timing diagram similar to Figure 3.7 and find the turnaround time for each process. Assume that the dispatcher takes 2.5 milliseconds for a process switch