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📜  LJF和LRJF CPU调度算法之间的区别

📅  最后修改于: 2021-08-24 04:33:37             🧑  作者: Mango

1.最长的工作优先(LJF):
它是CPU调度算法,其中首先执行突发行最大的进程。一旦进程进入就绪队列,该进程仅在执行完成后退出,因此它是一个非抢占式进程。如果进程的突发时间相同,则选择总时间最短的作业。此CPU调度算法导致系统的吞吐量较低。

Process AT BT
1 0 3
2 1 2
3 2 4
4 3 5
5 4 6

2.最长剩余工作优先(LRJF):
它是最长作业优先CPU调度算法的抢先版本。每秒选择过程“突发时间”,然后选择最长的作业。如果进程的突发时间相同,则选择总体到达时间短的作业。

由于同时检查了进程的剩余突发时间,因此它遭受了饥饿的困扰。它也被称为“最长剩余时间优先”算法。

Process AT BT
1 0 3
2 1 2
3 2 4
4 3 5
5 4 6

LJF和LRJF CPU调度算法之间的区别:

LJF LRJF
Non preemptive Preemptive
It suffers from starvation It also suffers from starvation
Waiting Time is high Waiting Time is not so high, and processes get chances for execution after some interval.
Switching context is less, since a process that once enters running state is executed completely. Switching context is more, since the process are continually checked for execution.
The processes are executed based on their CPU time and arrival time alone, without increasing CPU overload. The processes are repeatedly checking for an idle CPU, thereby increasing the overload.
No process can complete its execution until longest job persists. The processes can complete execution before the longest process.