import struct
import time


def bench_iter_unpack(buf, iters):
    for i in range(iters):
        list(struct.iter_unpack('I', buf))

def grouper(seq, size):
    for i in range(0, len(seq), size):
        yield seq[i: i + size]

def bench_grouper(buf, iters):
    for i in range(iters):
        unpack = struct.Struct('I').unpack
        [unpack(chunk)[0] for chunk in grouper(buf, 4)]

if __name__ == "__main__":
    buf = b"1234" * 100
    iters = 10000

    for bench_func in (bench_iter_unpack, bench_grouper):
        t1 = time.time()
        bench_func(buf, iters)
        t2 = time.time()
        print("%s -> %.1f ms." % (bench_func.__name__, (t2 - t1) * 1000))