DEV Community

Cover image for Python decorator to measure execution time
Kubernetes Community Days Chennai profile image Suresh Kumar
Suresh Kumar for Kubernetes Community Days Chennai

Posted on

Python decorator to measure execution time

#python #programming #beginners #webdev

In the previous articles on the Python decorator series, we have learnt decorators, how they work and to implement a simple function based decorator and a class based decorator and decorator that supports parameters. In this article, we will create reusable decorator utility to measure execution time of a function and instance method in a class.

Measure execution time of a function 

from functools import wraps import time def timeit(func): @wraps(func) def timeit_wrapper(*args, **kwargs): start_time = time.perf_counter() result = func(*args, **kwargs) end_time = time.perf_counter() total_time = end_time - start_time print(f'Function {func.__name__}{args} {kwargs} Took {total_time:.4f} seconds') return result return timeit_wrapper @timeit def calculate_something(num): """ Simple function that returns sum of all numbers up to the square of num. """ total = sum((x for x in range(0, num**2))) return total if __name__ == '__main__': calculate_something(10) calculate_something(100) calculate_something(1000) calculate_something(5000) calculate_something(10000)
Enter fullscreen mode Exit fullscreen mode

How it works

  1. We decorate the function with timeit decorator
  2. decorator makes note of start time
  3. then executes the function
  4. decorator marks end time
  5. calculates time difference and prints the time taken for the function

Output

Function calculate_something(10,) {} Took 0.0000 seconds Function calculate_something(100,) {} Took 0.0008 seconds Function calculate_something(1000,) {} Took 0.0760 seconds Function calculate_something(5000,) {} Took 2.4503 seconds Function calculate_something(10000,) {} Took 7.9202 seconds
Enter fullscreen mode Exit fullscreen mode

Measure execution time of a method inside a class 

from functools import wraps import time def timeit(func): @wraps(func) def timeit_wrapper(*args, **kwargs): start_time = time.perf_counter() result = func(*args, **kwargs) end_time = time.perf_counter() total_time = end_time - start_time # first item in the args, ie `args[0]` is `self`  print(f'Function {func.__name__}{args} {kwargs} Took {total_time:.4f} seconds') return result return timeit_wrapper class Calculator: @timeit def calculate_something(self, num): """ an example function that returns sum of all numbers up to the square of num """ total = sum((x for x in range(0, num**2))) return total def __repr__(self): return f'calc_object:{id(self)}' if __name__ == '__main__': calc = Calculator() calc.calculate_something(10) calc.calculate_something(100) calc.calculate_something(1000) calc.calculate_something(5000) calc.calculate_something(10000)
Enter fullscreen mode Exit fullscreen mode

How it works

  1. we decorate a method inside a class with timeit
  2. timeit takes all arguments, note that args[0] is self so you can call any other method inside the class using self
  3. decorator makes note of start time
  4. then executes the function
  5. decorator marks end time
  6. calculates time difference and prints the time taken for the function

Output

Function calculate_something(calc_object:140246512997904, 10) {} Took 0.0000 seconds Function calculate_something(calc_object:140246512997904, 100) {} Took 0.0007 seconds Function calculate_something(calc_object:140246512997904, 1000) {} Took 0.1820 seconds Function calculate_something(calc_object:140246512997904, 5000) {} Took 1.9241 seconds Function calculate_something(calc_object:140246512997904, 10000) {} Took 7.4005 seconds
Enter fullscreen mode Exit fullscreen mode

In the next article, we will implement various kinds decorator recipes. Stay tuned for upcoming articles. Subscribe to the newsletter and Connect with me on twitter to get my future articles.

Top comments (0)