What is performance?
Performance is a very broad term. It has many different meanings and, in many cases, it is defined incorrectly. Within this chapter, we will attempt to measure and improve performance in terms of CPU usage/time and memory usage. Many of the examples here are a trade-off between execution time and memory usage. Note that a fast algorithm that can only use a single CPU core can be outperformed in terms of execution time by a slower algorithm that is easily parallelizable given enough CPU cores.
When it comes to incorrect statements about performance, you have probably heard statements similar to “Language X is faster than Python.” That statement is inherently wrong. Python is neither fast nor slow; Python is a programming language, and a language has no performance metrics whatsoever. If you were to say that the CPython interpreter is faster or slower than interpreter Y for language X, that would be possible. The performance characteristics of...
