Understanding Software Dynamics

Chapter 9

Aggregate Measures

The performance analysist has an overall goal of understanding the dynamics of some software, understanding when and why it is slow, and understanding how to diminish the number and severity of slow transactions.

For a service processing 10,000 requests per second, there are nearly a billion requests per day (86,400 seconds per day). Just recording the arrival time of each request gives us ~1B data points, and recording anything else, such as latency or response size in bytes, gives us billions more. With a huge number of individual times or measurements, it will be useful to summarize them in several different ways, each with the purpose of revealing a different kind of performance problem. In this chapter, we will ...