compare (pool)

from time import time
import multiprocessing
from multiprocessing import Pool

# Initial params
piece_size = 16 # KB
# cores in system
multiplier = 4
errors = 0

starttime = time()

# 2 equal by size, but different by content files
file1 = open('etalon.mkv', 'rb')
file2 = open('startplus.mkv', 'rb')

# get byte piece of 2 files, and compare them
def check(r1, r2, i):
    global errors
    if r1[i:i + piece_size] != r2[i:i + piece_size]:
        errors += 1
    return

if __name__ == '__main__':
    # 4 process threads (opt for 4 core cpu)
    pool = Pool(processes = multiplier)

    r1 = file1.read(piece_size * multiplier)
    r2 = file2.read(piece_size * multiplier)

    while r1:
        for i in range(0, piece_size * multiplier, piece_size):
            pool.apply(check, [r1,r2,i])
        r1 = file1.read(piece_size)
        r2 = file2.read(piece_size)

    print('errors:', errors)
    print('Running time: ', time() - starttime)