How to occupy 80% CPU consistently?

Question

I\'m looking for a way to occupy exactly 80% (or any other number) of a single CPU in a consistent manner.
I need this for some unit test that tests a component that tri

Answer 1

The trick is that if you want to occupy 80% of CPU, keep the processor busy for 0.8 seconds (or 80% of any time interval. Here I take it to be 1 second), then let it sleep for 0.2 seconds, though it is advisable not to utilize the CPU too much, or all your processes will start running slow. You could try around 20% or so. Here is an example done in Python:

import time
import math
time_of_run = 0.1
percent_cpu = 80 # Should ideally replace this with a smaller number e.g. 20
cpu_time_utilisation = float(percent_cpu)/100
on_time = time_of_run * cpu_time_utilisation
off_time = time_of_run * (1-cpu_time_utilisation)
while True:
    start_time = time.clock()
    while time.clock() - start_time < on_time:
        math.factorial(100) #Do any computation here
    time.sleep(off_time)