Chapter 5 CPU Scheduling

______ allows a thread to run on a specific core/processor. A. Processor affinity B. Processor set C. NUMA D. Load balancing

A. Processor affinity

Which of the following scheduling algorithms gives the minimum average waiting time for a given set of processes? A. SJF B. FCFS C. RR D. Multilevel queue

A. SJF

What effect does the size of the time quantum have on the performance of an RR algorithm?

At one extreme, if the time quantum is extremely large, the RR policy is the same as the FCFS policy. If the time quantum is extremely small, then it has an overwhelmingly high context switch overhead.

Which of the following criteria is more important for an interactive system? A. CPU utilization B. Response time C. Turnaround time D. Throughput

B. Response time

A significant problem with priority scheduling algorithms is _____. A. complexity B. starvation C. determining the length of the next CPU burst D. determining the length of the time quantum

B. starvation

Which of the following scheduling algorithms must be nonpreemptive? A. SRTF B. RR C. FCFS D. PP

C. FCFS

The ____ scheduling algorithm is designed especially for time-sharing systems. A. SJF B. FCFS C. RR D. Multilevel queue

C. RR

Which of the following scheduling algorithms gives the minimum average response time? A. SJF B. FCFS C. RR D. PP

C. RR

Which of the following criteria is more important from the point of view of a non-interactive/batch process? A. CPU utilization B. Response time C. Turnaround time D. Throughput

C. Turnaround time

The ______ occurs in first-come-first-served scheduling when a process with a long CPU burst occupies the CPU. A. dispatch latency B. waiting time C. convoy effect D. system-contention scope

C. convoy effect

scheduling is approximated by predicting the next CPU burst with an exponential average of the measured lengths of previous CPU bursts. A. Multilevel queue B. RR C. FCFS D. SJF

D. SJF

____ is the number of processes that are completed per time unit. A. CPU utilization B. Response time C. Turnaround time D. Throughput

D. Throughput

(T/F) In RR scheduling, the time quantum should be small with respect to the context-switch time.

False

(T/F) Shortest-remaining-time-first scheduling is the non-preemptive version of SJF.

False

Explain the difference between response time and turnaround time. These times are both used to measure the effectiveness of scheduling schemes.

Response time is a measure of the time that elapses between a request and the first response produced.Turnaround time, on the other hand, represents the lifetime of a process, starting with its creation and ending with its termination.

Explain the process of starvation in the context of CPU scheduling and how aging can be used to prevent it in priority based schedulers.

Starvation occurs when a process is ready to run but is stuck waiting indefinitely for the CPU. This can be caused, for example, when higher-priority processes prevent low-priority processes from ever getting the CPU. Aging involves gradually increasing the priority of a process so that a process will eventually achieve a high enough priority to execute if it waited for a long enough period of time.

What role does the dispatcher play in CPU scheduling and what is dispatch latency?

The dispatcher gives control of the CPU to the process selected by the short-term scheduler. To perform this task, a context switch, a switch to user mode, and a jump to the proper location in the user program are all required. The dispatch should be made as fast as possible. The time lost to the dispatcher is termed dispatch latency.

(T/F) Round-robin (RR) scheduling degenerates to first-come-first-served (FCFS) scheduling if the time quantum is too long.

True