操作系统导论-进程

第四章:进程

作业来自: ostep-homework

  1. 两个程序都只使用CPU,所以CPU的利用率是100%,测试可得:

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    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

    Stats: Total Time 10
    Stats: CPU Busy 10 (100.00%)
    Stats: IO Busy 0 (0.00%)
  2. 总共使用了11 ticks的时间,测试可得:

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    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 WAITING 1
    11* DONE RUN:io_done 1
  3. 交换顺序后,在PID0进行io操作的时候,PID1会切换成RUNNING的状态,提高了CPU的利用效率,所以交换顺序重要。测试可得:

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    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 WAITING DONE 1
    7* RUN:io_done DONE 1
  4. 由于加上了SWITCH_ON_END的标签,此时PID0进行IO操作的时候CPU会空闲等待至IO操作完成,浪费了一定的时间。测试可得:

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    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 WAITING READY 1
    7* RUN:io_done READY 1
    8 DONE RUN:cpu 1
    9 DONE RUN:cpu 1
    10 DONE RUN:cpu 1
    11 DONE RUN:cpu 1
  5. 由于这次会在等待IO的时候进行进程的切换,所以在io操作时,CPU没有等待,而是切换到了另外一个进程上继续工作,提高了利用率。测试可得:

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    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 WAITING DONE 1
    7* RUN:io_done DONE 1
  6. 由于IO操作的优先级不是最高的,即使io操作的WAITING结束了,也会等待CPU先将其他进程执行之后,再对IO进行切换,由于IO操作需要消耗比较多的额外时间,而这部分时间没有被CPU利用,所以系统资源没有得到有效利用。测试可得:

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    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 WAITING RUN:cpu READY READY 1 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 DONE 1
    18 RUN:io DONE DONE DONE 1
    19 WAITING DONE DONE DONE 1
    20 WAITING DONE DONE DONE 1
    21 WAITING DONE DONE DONE 1
    22 WAITING DONE DONE DONE 1
    23 WAITING DONE DONE DONE 1
    24* RUN:io_done DONE DONE DONE 1
    25 RUN:io DONE DONE DONE 1
    26 WAITING DONE DONE DONE 1
    27 WAITING DONE DONE DONE 1
    28 WAITING DONE DONE DONE 1
    29 WAITING DONE DONE DONE 1
    30 WAITING DONE DONE DONE 1
    31* RUN:io_done DONE DONE DONE 1
  7. 在使用了IMMEDIATE标签后,每次io_done之后CPU都会先切换io操作,然后用io处理的时间来处理其他进程,提高了系统资源的利用率。测试如下:

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    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 WAITING RUN:cpu READY READY 1 1
    7* RUN:io_done DONE READY READY 1
    8 RUN:io DONE READY READY 1
    9 WAITING DONE RUN:cpu READY 1 1
    10 WAITING DONE RUN:cpu READY 1 1
    11 WAITING DONE RUN:cpu READY 1 1
    12 WAITING DONE RUN:cpu READY 1 1
    13 WAITING DONE RUN:cpu READY 1 1
    14* RUN:io_done DONE DONE READY 1
    15 RUN:io DONE DONE READY 1
    16 WAITING DONE DONE RUN:cpu 1 1
    17 WAITING DONE DONE RUN:cpu 1 1
    18 WAITING DONE DONE RUN:cpu 1 1
    19 WAITING DONE DONE RUN:cpu 1 1
    20 WAITING DONE DONE RUN:cpu 1 1
    21* RUN:io_done DONE DONE DONE 1
  8. 开放题随机,和前七题大致相同。


操作系统导论-进程
https://halc.top/p/e328a303
作者
HalcyonAzure
发布于
2022年3月12日
许可协议