Benchmarking code

Benchmarking measures the performance of a function or program, allowing you to compare implementations and to understand the performance impact of code changes. Using that information, you can easily reveal the part of the code that needs to be rewritten to improve its performance. It goes without saying that you should not benchmark Go code on a busy machine that is currently being used for other, more important, purposes unless you have a very good reason to do so! Otherwise, you might interfere with the benchmarking process and get inaccurate results, but most importantly, you might generate performance issues on the machine.

Most of the time, the load of the operating system plays a key role in the performance of your code. Let me tell you a story here: a Java utility I developed for a project performs lots of computations and finishes in 6,242 seconds when running on its own. It took about a day for four instances of the same Java command-line...