Simulate CPU load with Python

Simulate CPU load with Python

While testing out some home automation code on my Raspberry Pi I noticed it was pretty CPU intensive. Time to bump up the overclock to squeeze more performance out of the Broadcom Arm7 processor. I wanted to keep an eye on temps as well as stability under full load so I needed to simulate CPU usage.

This small Python script will do the job. It uses the multiprocessing library which you can read more about here.

#!/usr/bin/env python
"""
Produces load on all available CPU cores

Updated with suggestion to prevent Zombie processes
Linted for Python 3
Source: 
insaner @ http://danielflannery.ie/simulate-cpu-load-with-python/#comment-34130
"""
from multiprocessing import Pool
from multiprocessing import cpu_count

import signal

stop_loop = 0


def exit_chld(x, y):
    global stop_loop
    stop_loop = 1


def f(x):
    global stop_loop
    while not stop_loop:
        x*x


signal.signal(signal.SIGINT, exit_chld)

if __name__ == '__main__':
    processes = cpu_count()
    print('-' * 20)
    print('Running load on CPU(s)')
    print('Utilizing %d cores' % processes)
    print('-' * 20)
    pool = Pool(processes)
    pool.map(f, range(processes))


This will utilize each CPU core and produce ~100% load with the while loops calculation.

--------------------
Running load on CPU(s)
Utilizing 8 cores
--------------------

4 thoughts on “Simulate CPU load with Python”

    • Hi insaner,
      Nice job! Thanks for the credit. Your comment about the Zombie processes was also correct. I’ve updated the original post with your suggestions.

  1. I have noticed you don’t monetize danielflannery.ie, don’t waste your traffic,
    you can earn extra bucks every month with new monetization method.
    This is the best adsense alternative for any type of website (they approve all websites), for more info
    simply search in gooogle: murgrabia’s tools

  2. This creates a bunch of zombie processes. To avoid that:

    #!/usr/bin/env python
    “””
    Produces load on all available CPU cores
    # http://danielflannery.ie/simulate-cpu-load-with-python/
    “””
    from multiprocessing import Pool
    from multiprocessing import cpu_count

    import signal

    stop_loop = 0

    def exit_chld(x,y):
    global stop_loop
    stop_loop = 1

    def f(x):
    global stop_loop
    while not stop_loop:
    x*x

    signal.signal(signal.SIGINT, exit_chld)

    if __name__ == ‘__main__’:
    processes = cpu_count()
    print ‘-‘ * 20
    print ‘Running load on CPU’
    print ‘Utilizing %d cores’ % processes
    print ‘-‘ * 20
    pool = Pool(processes)
    pool.map(f, range(processes))

Leave a Comment