Time and profile your code

12 Apr 2020

Using timeit

timeit.timeit function only accepts strings. This can be quite annoying if you want to measure larger functions.

import timeit
timeit.timeit('"-".join(str(n) for n in range(10_000_000))', number=1)

2.7127743320000093

Using context manager

from contextlib import contextmanager
from time import time


@contextmanager
def timing(description: str) -> None:
    start = time()
    yield
    ellapsed_time = time() - start

    print(f"{description}: {ellapsed_time}")


with timing("List Comprehension Example"):
    s = [x for x in range(10_000_000)]

List Comprehension Example: 0.5566189289093018

Using class

from time import time

class TimeTook(object):
    """
    Calculates the time a block took to run.
    Example usage:
    with TimeTook("sample"):
        s = [x for x in range(10000000)]
    """
    def __init__(self, description):
        self.description = description

    def __enter__(self):
        self.start = time()

    def __exit__(self, type, value, traceback):
        self.end = time()
        print(f"Time took for {self.description}: {self.end - self.start}")
        
with TimeTook("List Comprehension Example"):
    s = [x for x in range(10_000_000)]

Time took for List Comprehension Example: 0.5780296325683594

Using SnakeViz

CLI

python -m cProfile -o program.prof my_program.py
snakeviz program.prof

IPython

%prun -D program.prof glob.glob('*.txt')

Single line

import glob
%load_ext snakeviz
%snakeviz glob.glob('*.*')

The snakeviz extension is already loaded. To reload it, use:
  %reload_ext snakeviz
 
*** Profile stats marshalled to file '/var/folders/wn/k3vlc_7s4mjcszy_1l54z5qm0000gn/T/tmpxau65ynn'. 
Embedding SnakeViz in this document...

Multiple lines

%%snakeviz
files = glob.glob('*.txt')
for file in files:
    with open(file) as f:
        print(hashlib.md5(f.read().encode('utf-8')).hexdigest())

*** Profile stats marshalled to file '/var/folders/wn/k3vlc_7s4mjcszy_1l54z5qm0000gn/T/tmpc8imb63p'. 
Embedding SnakeViz in this document...