94 lines
2.9 KiB
Markdown
94 lines
2.9 KiB
Markdown
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#lec10 进程／线程控制spoc练习
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## SPOC小组思考题
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(1) (spoc)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](https://github.com/chyyuu/ucore_lab/blob/master/related_info/lab5/process-cpu-cpuio-homework.py)，请理解代码，并完成＂YOUR CODE"部分的内容． 可２个人一组
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### 进程的状态
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```
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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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- WAIT - 进程等待I/O完成
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- DONE - 进程结束
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```
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### 进程的行为
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```
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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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- 发出I/O操作请求,放弃使用CPU
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```
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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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- 先查找位于proc_info队列的curr_proc元素(当前进程)之后的进程(curr_proc+1..end)是否处于READY态，
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- 再查找位于proc_info队列的curr_proc元素(当前进程)之前的进程(begin..curr_proc-1)是否处于READY态
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- 如都没有，继续执行curr_proc直到结束
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### 关键模拟变量
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- 进程控制块
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```
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PROC_CODE = 'code_'
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PROC_PC = 'pc_'
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PROC_ID = 'pid_'
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PROC_STATE = 'proc_state_'
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```
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- 当前进程 curr_proc
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- 进程列表：proc_info是就绪进程的队列（list），
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- 在命令行（如下所示）需要说明每进程的行为特征：（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yield指令（进程放弃CPU,进入READY状态）的比例(0..100)
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Ｚ是执行I/O请求指令（进程放弃CPU,进入WAIT状态）的比例(0..100)
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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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### 进程执行
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```
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instruction_to_execute = self.proc_info[self.curr_proc][PROC_CODE].pop(0)
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```
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### 关键函数
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- 系统执行过程：run
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- 执行状态切换函数: move_to_ready/running/done
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- 调度函数：next_proc
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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 5:30:30,5:40:30 -c
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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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io
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io
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yld
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cpu
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yld
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Process 1
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yld
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io
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yld
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yld
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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 or IO
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Time PID: 0 PID: 1 CPU IOs
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1 RUN:io READY 1
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2 WAITING RUN:yld 1 1
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3 WAITING RUN:io 1 1
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4 WAITING WAITING 2
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5 WAITING WAITING 2
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6* RUN:io WAITING 1 1
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7 WAITING WAITING 2
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8* WAITING RUN:yld 1 1
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9 WAITING RUN:yld 1 1
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10 WAITING RUN:yld 1 1
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11* RUN:yld DONE 1
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12 RUN:cpu DONE 1
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13 RUN:yld DONE 1
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```
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