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Modify 4-2 answer #24

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Modify 4-2 answer #24

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35 changes: 18 additions & 17 deletions 4/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -12,25 +12,26 @@ This program, `process-run.py`, allows you to see how process states change as p

2. Now run with these flags: `./process-run.py -l 4:100,1:0`.These flags specify one process with 4 instructions (all to use the CPU), and one that simply issues an I/O and waits for it to be done.How long does it take to complete both processes? Use `-c` and `-p` to find out if you were right.

4(process 0) + 5(process 1 IO) + 1 = 10
4(process 0) + 1(process 1 Run:IO ) + 5(process 1 IO) + 1(process 1 IO_Done) = 11

```
$ ./process-run.py -l 4:100,1:0 -c -p
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

Stats: Total Time 10
Stats: CPU Busy 5 (50.00%)
Stats: IO Busy 4 (40.00%)
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 BLOCKED 1
7 DONE BLOCKED 1
8 DONE BLOCKED 1
9 DONE BLOCKED 1
10 DONE BLOCKED 1
11* DONE RUN:io_done 1

Stats: Total Time 11
Stats: CPU Busy 6 (54.55%)
Stats: IO Busy 5 (45.45%)
```

3. Switch the order of the processes: `-l 1:0,4:100`. What happens now? Does switching the order matter? Why? (As always, use `-c` and `-p` to see if you were right)
Expand Down Expand Up @@ -66,4 +67,4 @@ This program, `process-run.py`, allows you to see how process states change as p

Now other proecss can run when process 0 is waiting IO. More fair and reduce response time.

8. Now run with some randomly generated processes: `-s 1 -l 3:50,3:50` or `-s 2 -l 3:50,3:50` or `-s 3 -l 3:50,3:50`. See if you can predict how the trace will turn out. What happens when you use the flag `-I IO_RUN_IMMEDIATE` vs. `-I IO_RUN_LATER`? What happens when you use `-S SWITCH_ON_IO` vs. `-S SWITCH_ON_END`?
8. Now run with some randomly generated processes: `-s 1 -l 3:50,3:50` or `-s 2 -l 3:50,3:50` or `-s 3 -l 3:50,3:50`. See if you can predict how the trace will turn out. What happens when you use the flag `-I IO_RUN_IMMEDIATE` vs. `-I IO_RUN_LATER`? What happens when you use `-S SWITCH_ON_IO` vs. `-S SWITCH_ON_END`?