Simple example of threading using all cpu threads available

parallel_test.py

from threading import Thread, Lock
from multiprocessing import cpu_count
from queue import Queue
import math
import random

lock = Lock()


def do_work(name, t):
    test = [math.tanh(a - b) for a in range(random.randint(500, 2000)) for b in range(random.randint(500, 2000))]
    lock.acquire()
    print("test done %.10f in %s on thread %d" % (sum(test), name, t))
    lock.release()


letters = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
           "w", "x", "y", "z"]
names = ["%s_%d" % (l, i) for l in letters for i in range(10)]


def worker():
    item = q.get()
    while len(names) > 0:
        do_work(names.pop(0), item)
    q.task_done()


q = Queue()
for i in range(cpu_count()):
    q.put(i)
    t = Thread(target=worker)
    t.daemon = True
    t.start()

q.join()  # block until all tasks are done