OS作业模拟SJF和FCFS OS作业模拟SJF和FCFS

一个OS的作业, 用于模拟短作业优先和先来先服务两种作业调度方式.

#!/usr/bin/python3.5## Modify the SJF and FCFS algorithm in the topic of dealing with jobs.job_num = 5class Job(): # 定义作业 def __init__(self, arr_time=-1, sev_time=-1, cpt_time=-1, wghted_run_time=-1): self.arr_time = arr_time self.sev_time = sev_time self.cpt_time = cpt_time self.wghted_run_time = wghted_run_time self.run_time = self.cpt_time - self.arr_time# 初始化工作 job0 = Job(arr_time=0, sev_time=4) job1 = Job(arr_time=1, sev_time=1) job2 = Job(arr_time=4, sev_time=2) job3 = Job(arr_time=5, sev_time=1) job4 = Job(arr_time=6, sev_time=3)job_list = []for i in range(job_num): job_list.append(locals()['job' + str(i)])def FCFS(job_list): # 先来先服务算法, 比较简单, 不赘述. avg_run_time = 0 avg_wght_run_time = 0 print('NO.\t\tarr_time\tsev_time\tweighted_run_time') curr_cpt_time = 0 for i in job_list: curr_cpt_time += i.sev_time i.cpt_time = curr_cpt_time i.wghted_run_time = (i.cpt_time - i.arr_time) / i.sev_time i.run_time = i.cpt_time - i.arr_time print("job{}\t{}\t\t\t{}\t\t\t{}".format(str(job_list.index(i)), i.arr_time, i.cpt_time, i.wghted_run_time)) avg_run_time = sum([i.run_time for i in job_list]) / len(job_list) avg_wght_run_time = sum([i.run_time for i in job_list]) / sum([i.sev_time for i in job_list]) print('avg_run_time: ', avg_run_time) print('avg_wght_run_time: ', avg_wght_run_time) return 0def SJF(job_list): # 短作业优先算法(非抢占式). job_list_back_up = job_list.copy() print('NO.\t\tarr_time\tsev_time\tweighted_run_time') curr_cpt_time = 0 curr_time = 0 # 预留初始作业表, 用于之后的确定作业序号. arr_time_list_initial = [i.arr_time for i in job_list.copy()] for n in range(len(job_list)): # 遍历先存的作业构成的作业表, 选出已经或刚好在等待的作业, 选出它们之中运行时间最短的. arr_time_list = [i.arr_time for i in job_list] for i in range(len(arr_time_list)): arr_time_list[i] -= curr_time arr_time_list[i] = max(0, arr_time_list[i])# 已经等待或刚好等待都记为刚到 min_list = [i for i in range(len(arr_time_list)) if arr_time_list[i] == min(arr_time_list)] # 选出刚到的作业的序号 t_list = [job_list[i] for i in min_list]# 将"刚到"的作业存入t_list ely_cpt_time = [i.sev_time for i in t_list]# 计算它们的服务时间 idx = ely_cpt_time.index(min(ely_cpt_time))# 选出"刚到"的作业中服务时间最短的 curr_job = job_list.pop(min_list[idx])# 选出目标作业, 进行一系列的操作 curr_job_no = arr_time_list_initial.index(curr_job.arr_time) curr_cpt_time += curr_job.sev_time curr_job.cpt_time = curr_cpt_time curr_job.wghted_run_time = (curr_job.cpt_time - curr_job.arr_time) / curr_job.sev_time curr_job.run_time = curr_job.cpt_time - curr_job.arr_time print("job{}\t{}\t\t\t{}\t\t\t{}".format(curr_job_no, curr_job.arr_time, curr_job.sev_time, curr_job.wghted_run_time)) curr_time += curr_job.sev_timeavg_run_time = sum([i.run_time for i in job_list_back_up]) / len(job_list_back_up) avg_wght_run_time = sum([i.run_time for i in job_list_back_up]) / sum([i.sev_time for i in job_list_back_up]) print('avg_run_time: ', avg_run_time) print('avg_wght_run_time: ', avg_wght_run_time) return 0while True: algorithm_choice = input("FCFS or SJF?\n") if algorithm_choice == 'FCFS': FCFS(job_list) break elif algorithm_choice == 'SJF': SJF(job_list) break elif algorithm_choice == 'q': break else: print("Invalid choice, enter 'q' to quit.\n")