CPU Scheduling computing the average response time and througput in FCFS SJF MultiLevel FB

package demo; import java.time.Duration; import java.time.Instant; import java.util.ArrayList; import java.util.List; import java.util.Random; class Process { int id; Instant ready; //The time the process enter the ready queue Instant starting_timing; //The time the process is picked up by CPU int burst_time; //CPU execution time Instant finishing_time; //The time that the process is finished by CPU Process(int i, List<Process> ready_q) { id = i; Instant cur_time = Instant.now(); //1. Let the process wait for a random amount of time and then set the time to the ready time (between 0 and 2000) Random rd = new Random(); int amount = rd.nextInt(2000) + 1; Duration d = Duration.ofMillis(amount); ready = cur_time.plus(d); //2. Assign a burst_time for the process burst_time = rd.nextInt(2000) + 1000; //between 1000ms and 3000ms to finish //3. Add the current process into ready_q ready_q.add(this); } } public class CPUScheduling { /*Finish the FCFS by computing the average waiting time, average response time and throughput and print them out*/ //Follow the algorithm of FCFS to start the processes in the ready_q public static void FCFS(List<Process> ready_q) { Instant global_time = Instant.now().plus(Duration.ofMillis(3000)); //Represent the time CPU start scheduling List<Process> finishing_q = new ArrayList<Process>(); /* Loop finding minimum process and remove it from the ready_q */ //Pick a process to start execution (assign "starting_timing" and "finishing_time") // Once a process is removed from the ready_q, you can add them to another list: finishing_q while(ready_q.size() > 0) { Instant big_time = Instant.now().plus(Duration.ofMillis(10000)); //Create a bigger timestamp than all of the processes.ready time in the queue int idx = -1; //The index that points to the process with minimum ready time //The following for loop will find the earliest job (with minimum ready_time) for(int i = 0; i < ready_q.size(); i++) { //find the minimum ready_time if(big_time.compareTo(ready_q.get(i).ready) > 0) { idx = i; big_time = ready_q.get(i).ready; } } System.out.print("The minimum one is: "); System.out.println(ready_q.get(idx).ready); //assign "starting_timing" and "finishing_time" ready_q.get(idx).starting_timing = global_time; ready_q.get(idx).finishing_time = ready_q.get(idx).starting_timing.plus(Duration.ofMillis(ready_q.get(idx).burst_time)); global_time = ready_q.get(idx).finishing_time; //remove it from ready_q and add it to the finishing_q finishing_q.add(ready_q.get(idx)); ready_q.remove(idx); } System.out.println("Finishing Q: "); int total_waiting = 0; for(int i = 0; i < finishing_q.size(); i++) { //Print out (1) Average waiting time (2) Average response time (3) Throughput System.out.print("[" + i + "]: start: "); System.out.print(finishing_q.get(i).starting_timing); System.out.print("| end: "); System.out.println(finishing_q.get(i).finishing_time); //Accumulate each process's waiting time = starting_time - ready total_waiting += Duration.between(finishing_q.get(i).ready, finishing_q.get(i).starting_timing).toMillis(); } //Compute the Average waiting time double avg_waiting = total_waiting / finishing_q.size(); System.out.println("Total waiting: " + total_waiting + ", avg waiting: " + avg_waiting); } /*SJF (preemptive): Finish this function by computing the average waiting time, average response time and throughput and print them out*/ public static void SJF_preemptive(List<Process> ready_q) { //global_time - represents the time CPU start performing scheduling Instant global_time; //Assign the global_time by using the minimum ready (time) among all the processes in the ready_q } /*SJF (preemptive): Finish this function by computing the average waiting time, average response time and throughput and print them out*/ public static void multiLevel_FB(List<Process> ready_q) { //global_time - represents the time CPU start performing scheduling Instant global_time; //Assign the global_time by using the minimum ready (time) among all the processes in the ready_q } public static void main(String args[]) { List<Process> ready_q = new ArrayList<Process>(); //Create 10 processes and then add them to the ready_q for(int i = 0; i < 10; i++) { Process p = new Process(i, ready_q); } for(int i = 0; i < ready_q.size(); i++) { System.out.print("[" + ready_q.get(i).id + "]: "); System.out.print(ready_q.get(i).ready); System.out.println(" | burst: " + ready_q.get(i).burst_time); } //FCFS FCFS(ready_q); //After all the processes are finished, print out the overall wait time. } }