操作系统导论习题解答（8. Multi-level Feedback）

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于 2022-10-14 19:00:00 发布

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本文链接：https://blog.youkuaiyun.com/astralcon/article/details/133050840

本文深入探讨了多级反馈队列（MLFQ）调度策略，通过不同示例分析其行为，包括单一长运行任务、短任务的插入以及I/O影响。还讨论了当前MLFQ存在的问题，如饥饿和调度器操纵。作业涉及模拟不同场景，调整参数以实现类似轮转调度的行为，并研究如何确保长时间运行的任务获得至少5%的CPU时间。

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0. 文件地址

Homework

1. MLFQ: Basic Rules

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2. Attempt #1: How To Change Priority

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2.1 Example 1: A Single Long-Running Job

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2.2 Example 2: Along Came A Short Job

In this example, there are two jobs: A, which is a long-running CPU-intensive job, and B, which is a short-running interactive job. Assume A has been running for some time, and then B arrives. What will happen? Will MLFQ approximate SJF for B? 在这里插入图片描述
A (shown in black) is running along in the lowest-priority queue (as would any long-running CPU intensive jobs); B (shown in gray) arrives at time T = 100, and thus is inserted into the highest queue; as its run-time is short (only 20 ms), B complet