determining a process run time with python



~2 min read


240 words

I was recently trying to find the parts of my python application that were lagging in performance and so I went in search of a way to document how long things took.

I found this interesting approach based on PaulMcG’s answer on Stack Overflow:
import atexit
from time import time, strftime, localtime
from datetime import timedelta

def secondsToStr(elapsed=None):
    if elapsed is None:
        return strftime("%Y-%m-%d %H:%M:%S", localtime())
        return str(timedelta(seconds=elapsed))

def log(s, elapsed=None):
    line = "="*40
    print(secondsToStr(), '-', s)
    if elapsed:
        print("Elapsed time:", elapsed)

def endlog():
    end = time()
    elapsed = end-start
    log("End Program", secondsToStr(elapsed))

start = time()
log("Start Program")

I hadn’t previously encountered the atexit module, but love how easy it is to register an event to execute on a normal termination.

Using this approach per PaulMcG’s guidance also introduced me to the site-packages directory1 in which he stories the file allowing for importing it into any future python applications with a simple import timing at the top.

The timing.log function can be inserted to help narrow logs to a specific part of the application.

A nice recipe to have on hand for the future!


  • 1 The sites-packages seems to be roughly equivalent to a global node_modules directory. Per the README in my site-packages installed via .pyenv (~/.pyenv/versions/3.8.0/lib/python3.8/site-packages/):
This directory exists so that 3rd party packages can be installed here.  Read the source for for more details.

Hi there and thanks for reading! My name's Stephen. I live in Chicago with my wife, Kate, and dog, Finn. Want more? See about and get in touch!