Scheduling criteria(准则)T92(p385) 令 User oriented, Performance related(面向用户,考虑 性能) Response time(响应时间). from the submission (*x) of a request until the response begins to be received. often be used in time-shared time Turnaround(周转)time. The interval(间隙)of time between the submission of a process and its completion. Often be used in batch systems. Deadlines(截止期). The deadlines be specified for a process, such as starting deadlines and completion deadlines PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Scheduling Criteria（准则）T9.2(p385) ❖ User Oriented, Performance Related（面向用户，考虑 性能） ٭ Response time（响应时间）. From the submission （提交） of a request until the response begins to be received. Often be used in time-shared time. ٭ Turnaround（周转）time. The interval（间隙） of time between the submission of a process and its completion. Often be used in batch systems. ٭ Deadlines（截止期）. The deadlines be specified for a process, such as starting deadlines and completion deadlines
Scheduling Criteria (D) ☆ System Oriented(面向系统) Throughput(吞吐量). The number of pi rocesses completed per unit of time. Often used in batch system. Processor utilization(利用率). Percentage of time that the processor is busy. Balancing(平衡) Resources. Used in long-term and middle-term scheduling. Fairness(At). No process should suffer starvation (受饥饿 PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Scheduling Criteria （II） ❖ System Oriented（面向系统） ٭ Throughput （ 吞吐量 ） . The number of processes completed per unit of time. Often used in batch system. ٭ Processor Utilization（利用率）. Percentage of time that the processor is busy. ٭ Balancing（平衡）Resources. Used in long-term and middle-term scheduling. ٭ Fairness（公平）. No process should suffer starvation （受饥饿）
Scheduling Criteria (Im ☆ System Oriented Enforcing priorities(优先权). The scheduling policy should favor higher priority processes. Implement(实现): Multi-queue F94(P386) To avoid starve. consider the waiting time as a faction(因素) to calculate priority. PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Scheduling Criteria （III） ❖ System Oriented ٭ Enforcing priorities( 优先权 ). The scheduling policy should favor higher priority processes. ▪ Implement（实现）: Multi-queue F9.4(P386) ▪ To avoid starve, consider the waiting time as a faction（因素）to calculate priority
Multi-queue(多队列p386) ROO Release 口 DIspatch Processor ROI AdmIt ROn Preemption Event waIt E vent B locked Queue Priority Queuing PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Multi-queue（多队列p386）
Scheduling algorithms(p388) ☆ Selection function: °w: time spent waiting for the processor(从提交到现在的 等待时间) e: time spent in execution so far(到现在的执行时间) s: total service time required by the process, include e(an 要被服务的总时间) PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Scheduling Algorithms(p388) ❖ Selection function: ٭ w: time spent waiting for the processor(从提交到现在的 等待时间) ٭ e: time spent in execution so far(到现在的执行时间) ٭ s: total service time required by the process, include e(需 要被服务的总时间)