Sure, but if it's a python application, you have two options: 1) Tweak the code without understanding* of how it'll affect performance, because every single li

Sure, but if it's a python application, you have two options: 1) Tweak the code without understanding* of how it'll affect performance, because every single line of code hides behind it such complexity that any improvement you find is almost certainly overfitted to your version of Python. Eventually a benchmark will spit out a nice number. If successful, make a modest improvement, maybe 30%. 2) Rewrite the critical section in C. If you need to optimize further, you are now able to draw on 50 years of know-how in a well-studied field. The improvement will be on the order of thousands of percent. They both take about the same amount of time. Why should you do (1)? * There is a difference between random tips like "replace {} with dict()" and fundamentals like how the CPU cache works, or the branch predictor. The former is almost certainly a quirk of the current Python version, the latter has been the same for the past 20-30 years. If you do work on software performance, you rely on your knowledge of the fundamentals and a tool like `perf` to make educated guesses about where you can save some cycles. These fundamentals are basically irrelevant to Python code and so you have to make effectively random attempts.