import threading

import random

random.seed(0)

import time

def update(pause_period):

global counter

with count_lock:

current_counter = counter # reading in shared resource

time.sleep(pause_period) # simulating heavy calculations

counter = current_counter + 1 # updating shared resource

pause_periods = [random.randint(0, 1) for i in range(20)]

###########################################################################

counter = 0

count_lock = threading.Lock()

start = time.perf_counter()

for i in range(20):

update(pause_periods[i])

print("--Sequential version--")

print(f"Final counter: {counter}.")

print(f"Took {time.perf_counter() - start : .2f} seconds.")

###########################################################################

counter = 0

threads = [threading.Thread(target=update, args=(pause_periods[i],)) for i in range(20)]

start = time.perf_counter()

for thread in threads:

thread.start()

for thread in threads:

thread.join()

print("--Concurrent version--")

print(f"Final counter: {counter}.")

print(f"Took {time.perf_counter() - start : .2f} seconds.")

###########################################################################

print("Finished.")