Objectives

You will:

  • understand what profiling is
  • why it is important to profile code
  • know how to choose your test case

What is profiling

Profiling helps you understand how much time is spent in different parts of your code when it runs. These can be functions, loops, or source code lines.

Profiling information is obtained by using profiling tools. More on how to apply such tools at:

Why should I profile my code?

Obtaining profiling information is a critical step before attempting to optimise code, as it enables you to focus your efforts on improving the parts of the code that will result in the biggest gains in performance.

Choose your test case wisely

Due to the possible overhead from profiling tools, the code could run slower than normal. Therefore it is advisable to choose a small but representative test case to profile. That is, something that is representative of what you eventually want to run but completes in a short time.

The run time should not be too short, however, as this could make profiling results unreliable. Depending on the complexity of the code, the execution should take at least 10 seconds.

Note: keep in mind that with shortened computation time, the initialisation and finalisation steps may become dominant.