Linux: This Book Includes 4 Manuscripts. The Underground Bible to the unix operating System with Tools On Security and Kali Hacking to Understand Computer Programming, Data Science and Command Line

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Linux This Book Includes 4 Manuscripts The Underground Bible

Priority Planning
Circular duty scheduling assumes that all flows are equally
important. Otherwise, prioritized planning should be used. The basic idea
is simple: each thread is given priority, while the highest priority stream
from the queue of ready threads will be executed. Priorities can be given
statically or dynamically.
One of the approaches to the implementation of planning priorities
algorithm is multi-queue ( multilevel queues ). In this case, several bursts
organize groups with different priorities streams (streams each group
usually have different purposes).
The decision to choose the thread to execute is made as follows:
❖
If the highest priority streams are streams, they should use a simpler
scheduling algorithm (such as circular scheduling), without regard for
streams in other queues
❖
If there are no threads in the queue, the threads with the lower it
priority move to the queue
Different scheduling algorithms can be used for different queues, and each
queue can be allocated a certain amount of CPU time. Sharing priorities is a
difficult task, and failing to resolve them can cause streams of low priority
processes to wait a long time. For example, in 1973, a machine was stopped
at the Massachusetts Institute of Technology, which found a low-priority
process - it was queued for execution in 1967 and has not been able to run
since. This situation is called starvation.
There are different ways to solve the problem of starvation. For example, a
scheduler can gradually reduce the priority of the stream they perform (this
process is called aging), and when it becomes lower than the next priority

stream, switch the context to that stream. You can, on the contrary,
gradually increase the priority flows waiting in UT.

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