There are many situations where we find that our code runs too slow and we don’t know the apparent reason. For such situations it comes very handy to use the python cProfile module. The module enables us to see the time individual steps in our code take, as well as the number of times certain functions are being called. In the following paragraphs, I will explore it’s capabilities a bit more.
However first let’s remember the quote by Donald Knuth: “premature optimization is the root of all evil (or at least most of it) in programming”. So make sure that you don’t start optimizing before you even have a working code! In many cases you will not be able to determine the bottlenecks beforehand and might spend a lot of extra effort in the wrong places.
Profiling with cProfile
The easiest way of using the cProfile module from within a Python script can look as follows
import cProfile pr = cProfile.Profile() pr.enable() call_function() pr.disable() pr.print_stats(sort='time')
In the code we create a Profile object and enable it, then execute the code that is of interest to us, disable the profiling and view the results.