答案Github库
https://github.com/jzplp/OSTEP-Answers
- 问题 1 答案
[testjz@localhost cpu-intro]$ ./process-run.py -l 5:100,5:100
Produce a trace of what would happen when you run these processes:
Process 0
cpu
cpu
cpu
cpu
cpu
Process 1
cpu
cpu
cpu
cpu
cpu
Important behaviors:
System will switch whenthe current process is FINISHED or ISSUES AN IO
After IOs, the process issuing the IO willrun LATER (when it is its turn)
[testjz@localhost cpu-intro]$ ./process-run.py -l 5:100,5:100 -c
Time PID: 0 PID: 1 CPU IOs
1 RUN:cpu READY 1
2 RUN:cpu READY 1
3 RUN:cpu READY 1
4 RUN:cpu READY 1
5 RUN:cpu READY 1
6 DONE RUN:cpu 1
7 DONE RUN:cpu 1
8 DONE RUN:cpu 1
9 DONE RUN:cpu 1
10 DONE RUN:cpu 1
[testjz@localhost cpu-intro]$
- 问题 2 答案
[testjz@localhost cpu-intro]$ ./process-run.py -l 4:100,1:0
Produce a trace of what would happen when you run these processes:
Process 0
cpu
cpu
cpu
cpu
Process 1
io
Important behaviors:
System will switch whenthe current process is FINISHED or ISSUES AN IO
After IOs, the process issuing the IO willrun LATER (when it is its turn)
[testjz@localhost cpu-intro]$ ./process-run.py -l 4:100,1:0 -c
Time PID: 0 PID: 1 CPU IOs
1 RUN:cpu READY 1
2 RUN:cpu READY 1
3 RUN:cpu READY 1
4 RUN:cpu READY 1
5 DONE RUN:io 1
6 DONE WAITING 1
7 DONE WAITING 1
8 DONE WAITING 1
9 DONE WAITING 1
10* DONE DONE 1
[testjz@localhost cpu-intro]$
- 问题 3 答案
[testjz@localhost cpu-intro]$ ./process-run.py -l 1:0,4:100
Produce a trace of what would happen when you run these processes:
Process 0
io
Process 1
cpu
cpu
cpu
cpu
Important behaviors:
System will switch whenthe current process is FINISHED or ISSUES AN IO
After IOs, the process issuing the IO willrun LATER (when it is its turn)
[testjz@localhost cpu-intro]$ ./process-run.py -l 1:0,4:100 -c
Time PID: 0 PID: 1 CPU IOs
1 RUN:io READY 1
2 WAITING RUN:cpu 1 1
3 WAITING RUN:cpu 1 1
4 WAITING RUN:cpu 1 1
5 WAITING RUN:cpu 1 1
6* DONE DONE 1
[testjz@localhost cpu-intro]$
- 问题 4 答案
[testjz@localhost cpu-intro]$ ./process-run.py -l 1:0,4:100 -c -S SWITCH_ON_END
Time PID: 0 PID: 1 CPU IOs
1 RUN:io READY 1
2 WAITING READY 1
3 WAITING READY 1
4 WAITING READY 1
5 WAITING READY 1
6* DONE RUN:cpu 1
7 DONE RUN:cpu 1
8 DONE RUN:cpu 1
9 DONE RUN:cpu 1
[testjz@localhost cpu-intro]$
- 问题 5 答案
[testjz@localhost cpu-intro]$ ./process-run.py -l 1:0,4:100 -c -S SWITCH_ON_IO
Time PID: 0 PID: 1 CPU IOs
1 RUN:io READY 1
2 WAITING RUN:cpu 1 1
3 WAITING RUN:cpu 1 1
4 WAITING RUN:cpu 1 1
5 WAITING RUN:cpu 1 1
6* DONE DONE 1
[testjz@localhost cpu-intro]$
- 问题 6 答案
[testjz@localhost cpu-intro]$ ./process-run.py -l 3:0,5:100,5:100,5:100 -S SWITCH_ON_IO -I IO_RUN_LATER -c -p
Time PID: 0 PID: 1 PID: 2 PID: 3 CPU IOs
1 RUN:io READY READY READY 1
2 WAITING RUN:cpu READY READY 1 1
3 WAITING RUN:cpu READY READY 1 1
4 WAITING RUN:cpu READY READY 1 1
5 WAITING RUN:cpu READY READY 1 1
6* READY RUN:cpu READY READY 1
7 READY DONE RUN:cpu READY 1
8 READY DONE RUN:cpu READY 1
9 READY DONE RUN:cpu READY 1
10 READY DONE RUN:cpu READY 1
11 READY DONE RUN:cpu READY 1
12 READY DONE DONE RUN:cpu 1
13 READY DONE DONE RUN:cpu 1
14 READY DONE DONE RUN:cpu 1
15 READY DONE DONE RUN:cpu 1
16 READY DONE DONE RUN:cpu 1
17 RUN:io DONE DONE DONE 1
18 WAITING DONE DONE DONE 1
19 WAITING DONE DONE DONE 1
20 WAITING DONE DONE DONE 1
21 WAITING DONE DONE DONE 1
22* RUN:io DONE DONE DONE 1
23 WAITING DONE DONE DONE 1
24 WAITING DONE DONE DONE 1
25 WAITING DONE DONE DONE 1
26 WAITING DONE DONE DONE 1
27* DONE DONE DONE DONE 1
Stats: Total Time 27
Stats: CPU Busy 19 (70.37%)
Stats: IO Busy 12 (44.44%)
[testjz@localhost cpu-intro]$
- 问题 7 答案
[testjz@localhost cpu-intro]$ ./process-run.py -l 3:0,5:100,5:100,5:100 -S SWITCH_ON_IO -I IO_RUN_IMMEDIATE -c -p
Time PID: 0 PID: 1 PID: 2 PID: 3 CPU IOs
1 RUN:io READY READY READY 1
2 WAITING RUN:cpu READY READY 1 1
3 WAITING RUN:cpu READY READY 1 1
4 WAITING RUN:cpu READY READY 1 1
5 WAITING RUN:cpu READY READY 1 1
6* RUN:io READY READY READY 1
7 WAITING RUN:cpu READY READY 1 1
8 WAITING DONE RUN:cpu READY 1 1
9 WAITING DONE RUN:cpu READY 1 1
10 WAITING DONE RUN:cpu READY 1 1
11* RUN:io DONE READY READY 1
12 WAITING DONE RUN:cpu READY 1 1
13 WAITING DONE RUN:cpu READY 1 1
14 WAITING DONE DONE RUN:cpu 1 1
15 WAITING DONE DONE RUN:cpu 1 1
16* DONE DONE DONE RUN:cpu 1
17 DONE DONE DONE RUN:cpu 1
18 DONE DONE DONE RUN:cpu 1
Stats: Total Time 18
Stats: CPU Busy 18 (100.00%)
Stats: IO Busy 12 (66.67%)
[testjz@localhost cpu-intro]$
因为有过IO操作的进程很有可能后面也会进行IO操作，为了使CPU有效利用，应该在IO结束不久后运行该进程，使其得到继续阻塞IO的机会。
- 问题 8 答案
随机测试，无答案。
