CPU scheduling should preserve fairness and avoid processes from do not ever obtain CPU. Modern operating system era faces multitasking on computer operational environment. If CPU scheduling is efficient, high computation could be done correctly and system could be retained stable. One criterion that must be achieved by scheduling algorithm is minimization average waiting time for a set of processes in gaining CPU allocation. There are several algorithms for CPU scheduling; one of them is round robin. Round robin supplies quantum that is same for each of processes.