PDL Abstract

The Most Common Queueing Theory Questions Asked by Computer Systems Practitioners

First International Workshop on Teaching Performance Analysis of ComputerSystems (TeaPACS 2021) In conjunction with the IFIP Performance 2021 Conference. Milan, Italy, Nov 2021.

Mor Harchol-Balter, Ziv Scully

Carnegie Mellon University

This document examines five performance questions which are repeatedly asked by practitioners in industry: (i) My system utilization is very low, so why are job delays so high? (ii) What should I do to lower job delays? (iii) How can I favor short jobs if I don't know which jobs are short? (iv) If some jobs are more important than others, how do I negotiate importance versus size? (v) How do answers change when dealing with a closed-loop system, rather than an open system? All these questions have simple answers through queueing theory. This short paper elaborates on the questions and their answers. To keep things readable, our tone is purposely informal throughout. For more formal statements of these questions and answers, please see [14].