block vs single-byte write

test.py

from time import perf_counter
from contextlib import contextmanager

N = 1000000
BLOCK_SIZE = 10000

@contextmanager
def measure_time(name):
    start_time = perf_counter()
    yield
    
    print(f'Execution for "{name}" took {perf_counter()-start_time}')
    

with open('/tmp/test', 'wb') as fd:
    with measure_time('single'):
        for _ in range(N):
            fd.write(b'0')
            
        fd.flush()
    
    with measure_time('block'):
        for _ in range(N // BLOCK_SIZE):
            fd.write(b'0' * BLOCK_SIZE)
            
        fd.flush()
    
    
# Execution for "single" took 0.17417324799998823
# Execution for "block" took 0.0005379629997150914