2015-04-07 10:21:28 +08:00
|
|
|
|
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
|
|
|
|
|
|
|
|
|
|
|
|
### 进程的状态
|
|
|
|
|
|
|
|
|
|
|
|
- RUNNING - 进程正在使用CPU
|
|
|
|
|
|
- READY - 进程可使用CPU
|
|
|
|
|
|
- DONE - 进程结束
|
|
|
|
|
|
|
|
|
|
|
|
### 进程的行为
|
|
|
|
|
|
- 使用CPU,
|
|
|
|
|
|
- 发出YIELD请求,放弃使用CPU
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
### 进程调度
|
|
|
|
|
|
- 使用FIFO/FCFS：先来先服务
|
|
|
|
|
|
|
|
|
|
|
|
### 关键模拟变量
|
|
|
|
|
|
- 进程列表：描述了进程的行为特征：（１）使用CPU ;(2)等待I/O
|
|
|
|
|
|
```
|
|
|
|
|
|
-l PROCESS_LIST, --processlist= X1:Y1,X2:Y2,...
|
|
|
|
|
|
X 是进程的执行指令数;
|
|
|
|
|
|
Ｙ是执行CPU的比例(0..100) ，如果是100，表示不会发出yield操作
|
|
|
|
|
|
```
|
|
|
|
|
|
- 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
|
|
|
|
|
|
|
2015-04-08 11:24:18 +08:00
|
|
|
|
### 进程执行
|
|
|
|
|
|
```
|
|
|
|
|
|
instruction_to_execute = self.proc_info[self.curr_proc][PROC_CODE].pop(0)
|
|
|
|
|
|
```
|
2015-04-07 10:21:28 +08:00
|
|
|
|
### 执行实例
|
|
|
|
|
|
|
|
|
|
|
|
#### 例１
|
|
|
|
|
|
```
|
|
|
|
|
|
$./process-simulation.py -l 5:50
|
|
|
|
|
|
Process 0
|
|
|
|
|
|
yld
|
|
|
|
|
|
yld
|
|
|
|
|
|
cpu
|
|
|
|
|
|
cpu
|
|
|
|
|
|
yld
|
|
|
|
|
|
|
|
|
|
|
|
Important behaviors:
|
|
|
|
|
|
System will switch when the current process is FINISHED or ISSUES AN YIELD
|
|
|
|
|
|
Time PID: 0
|
|
|
|
|
|
1 RUN:yld
|
|
|
|
|
|
2 RUN:yld
|
|
|
|
|
|
3 RUN:cpu
|
|
|
|
|
|
4 RUN:cpu
|
|
|
|
|
|
5 RUN:yld
|
|
|
|
|
|
|
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
#### 例２
|
|
|
|
|
|
```
|
|
|
|
|
|
$./process-simulation.py -l 5:50,5:50
|
|
|
|
|
|
Produce a trace of what would happen when you run these processes:
|
|
|
|
|
|
Process 0
|
|
|
|
|
|
yld
|
|
|
|
|
|
yld
|
|
|
|
|
|
cpu
|
|
|
|
|
|
cpu
|
|
|
|
|
|
yld
|
|
|
|
|
|
|
|
|
|
|
|
Process 1
|
|
|
|
|
|
cpu
|
|
|
|
|
|
yld
|
|
|
|
|
|
cpu
|
|
|
|
|
|
cpu
|
|
|
|
|
|
yld
|
|
|
|
|
|
|
|
|
|
|
|
Important behaviors:
|
|
|
|
|
|
System will switch when the current process is FINISHED or ISSUES AN YIELD
|
|
|
|
|
|
Time PID: 0 PID: 1
|
|
|
|
|
|
1 RUN:yld READY
|
|
|
|
|
|
2 READY RUN:cpu
|
|
|
|
|
|
3 READY RUN:yld
|
|
|
|
|
|
4 RUN:yld READY
|
|
|
|
|
|
5 READY RUN:cpu
|
|
|
|
|
|
6 READY RUN:cpu
|
|
|
|
|
|
7 READY RUN:yld
|
|
|
|
|
|
8 RUN:cpu READY
|
|
|
|
|
|
9 RUN:cpu READY
|
|
|
|
|
|
10 RUN:yld READY
|
|
|
|
|
|
11 RUNNING DONE
|
|
|
|
|
|
```
|
