import threading
import time
import PIL.Image

src = PIL.Image.open('1.png')

def do_work(iters):
    for _ in range(iters):
        tmp = src.resize((640, 480))


def check(n_threads, total_iters=96):
    per_thread = total_iters // n_threads
    print('Check for {} threads and {} iterations ({} per thread)'.format(
        n_threads, total_iters, per_thread))
    threads = [threading.Thread(target=do_work, args=(per_thread,))
               for _ in range(n_threads)]
    t0 = time.time()
    for thread in threads:
        thread.start()
    for thread in threads:
        thread.join()
    dt = time.time() - t0
    print("Total time: {:.3f}s, per thread: {:.3f}s, per iteration in thread: {:.3f}s, per iteration total: {:.3f}s".format(
        dt, dt / n_threads, dt / per_thread, dt / total_iters))

for n_threads in range(1, 4+1):
    check(n_threads, 96)

"""
Check for 1 threads and 96 iterations (96 per thread)
Total time: 6.152s, per thread: 6.152s, per iteration in thread: 0.064s, per iteration total: 0.064s
Check for 2 threads and 96 iterations (48 per thread)
Total time: 6.664s, per thread: 3.332s, per iteration in thread: 0.139s, per iteration total: 0.069s
Check for 3 threads and 96 iterations (32 per thread)
Total time: 6.239s, per thread: 2.080s, per iteration in thread: 0.195s, per iteration total: 0.065s
Check for 4 threads and 96 iterations (24 per thread)
Total time: 6.346s, per thread: 1.587s, per iteration in thread: 0.264s, per iteration total: 0.066s
"""