Priority aging as a process scheduling strategy. What are the advantages and drawbacks?

Question

I have been doing some research on priority scheduling algorithms, and although I find Priority Aging to be a very basic (and seemingly sound) strategy, I can barely find information about it. Could someone please let me know the issues and advantages of implementing an algorithm? Thanks!

Answer 1

It appears that priority aging changes the priority of a task (usually lower) depending on how long the task has been running and / or how many resources the task consumes.

IBM has an explanation of the priority aging in DB2 version 9.7 for Linux, Unix, and Windows.

The biggest advantage of priority aging comes from the IBM explanation:

A simple approach that you can use to help short queries to run faster is to define a series of service classes with successively lower levels of resource priority and threshold actions that move activities between the service subclasses. Using this setup, you can decrease, or age, the priority of longer-running work over time and perhaps improve response times for shorter-running work without having detailed knowledge of the activities running on your data server.

The biggest disadvantage is that priority aging is harder to implement than a first-in, first-out queue, and may not provide any response time improvement.