ABSTRACT
This sounds easy, but it’s not. Even experienced programmers have a hard time identifying bottlenecks in their code. Instead of relying on your intuition, you should profile your code: use realistic inputs and measure the run-time of each individual operation. Only once you’ve identified the most important bottlenecks can you attempt to eliminate them. It’s difficult to provide general advice on improving performance, but I try my best with six techniques that can be applied in many situations. I’ll also suggest a general strategy for performance optimisation that helps ensure that your faster code will still be correct code. It’s easy to get caught up in trying to remove all bottlenecks. Don’t! Your time is valuable and is better spent analysing your data, not eliminating possible inefficiencies in your code. Be pragmatic: don’t spend hours of your time to save seconds of computer time. To enforce this advice, you should set a goal time for your code and optimise only up to that goal. This means you will not eliminate all bottlenecks. Some you will not get to because you’ve met your goal. Others you may need to pass over and accept either because there is no quick and easy solution or because the code is already well optimised and no significant improvement is possible. Accept these possibilities and move on to the
• Section 17.1 describes how to find the bottlenecks in your code using line profiling.
