Consider n processes sharing the CPU in a round-robin fashion. Assuming that…
1998
Consider n processes sharing the CPU in a round-robin fashion. Assuming that each process switch takes s seconds, what must be the quantum size q such that the overhead resulting from process switching is minimized but at the same time each process is guaranteed to get its turn at the CPU at least every t seconds?
- A.
q ≤ (t − ns)/(n − 1)
- B.
q ≥ (t − ns)/(n − 1)
- C.
q ≤ (t − ns)/(n + 1)
- D.
q ≥ (t − ns)/(n + 1)
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Correct answer: A
In round-robin scheduling with n processes, a process waits for the other n-1 processes to complete their quantum plus context switch overheads. The total wait time is (n-1)q + ns, which must not exceed the maximum allowed interval t. Solving for q yields q ≤ (t - ns)/(n-1). To minimize overhead, the quantum should be maximized within this limit.
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