Various Times of Process

When a process is created, it passes through various time intervals to complete its execution. Before explaining various scheduling algorithms, it is important to explain the various times of the process.

Various Times of Process 

Arrival time: When a process arrives in the ready queue.

Completion times: The Time at which a process completes its execution.

Burst Time or Execution Time:  The Total Execution Time of a process on the CPU. It is the running time of a process on the CPU. It has no concern with waiting time.

Burst time = turnaround time – Waiting time.

Turnaround Time: = Waiting time + Burst time OR Turnaround Time = completion time – arrival time

Waiting Time: Total time spent by a process when it enters into Ready Queue to completion of that process except the time of CPU execution for that process.

Waiting time = turnaround time – burst time

Response time: = the time at which a process gets CPU first time – arrival time

Throughput: The number of processes that complete their execution per unit of time is called Throughput.

Note: Every process has to wait for the CPU. So that its execution could be done. Execution of a process depends on CPU scheduling algorithms.