84 lines
1.7 KiB
Markdown
84 lines
1.7 KiB
Markdown
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设计一个简化的进程管理子系统，可以管理并调度如下简化进程.给出了参考代码
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### 进程的状态
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- RUNNING - 进程正在使用CPU
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- READY - 进程可使用CPU
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- DONE - 进程结束
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### 进程的行为
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- 使用CPU,
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- 发出YIELD请求,放弃使用CPU
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### 进程调度
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- 使用FIFO/FCFS：先来先服务
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### 关键模拟变量
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- 进程列表：描述了进程的行为特征：（１）使用CPU ;(2)等待I/O
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```
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-l PROCESS_LIST, --processlist= X1:Y1,X2:Y2,...
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X 是进程的执行指令数;
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Ｙ是执行CPU的比例(0..100) ，如果是100，表示不会发出yield操作
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```
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- 进程切换行为：系统决定何时(when)切换进程:进程结束或进程发出yield请求
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### 执行实例
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#### 例１
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```
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$./process-simulation.py -l 5:50
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Process 0
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yld
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yld
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cpu
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cpu
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yld
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Important behaviors:
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System will switch when the current process is FINISHED or ISSUES AN YIELD
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Time PID: 0
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1 RUN:yld
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2 RUN:yld
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3 RUN:cpu
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4 RUN:cpu
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5 RUN:yld
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```
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#### 例２
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```
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$./process-simulation.py -l 5:50,5:50
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Produce a trace of what would happen when you run these processes:
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Process 0
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yld
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yld
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cpu
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cpu
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yld
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Process 1
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cpu
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yld
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cpu
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cpu
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yld
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Important behaviors:
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System will switch when the current process is FINISHED or ISSUES AN YIELD
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Time PID: 0 PID: 1
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1 RUN:yld READY
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2 READY RUN:cpu
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3 READY RUN:yld
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4 RUN:yld READY
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5 READY RUN:cpu
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6 READY RUN:cpu
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7 READY RUN:yld
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8 RUN:cpu READY
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9 RUN:cpu READY
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10 RUN:yld READY
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11 RUNNING DONE
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```
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