debug_and_sync_code_in_executor.py

import time, asyncio, hashlib


def sync_cpu_bound():
    s = bytes(range(256))
    for i in range(100000):
        hashlib.sha256(s)

start = time.time()
sync_cpu_bound()
calc_time = time.time() - start


async def c0():
    t = asyncio.Task(tf('c0'))
    await asyncio.sleep(calc_time)
    t.cancel()

async def c1():
    t = asyncio.Task(tf('c1'))
    await asyncio.sleep(0)
    sync_cpu_bound()
    await asyncio.sleep(0)
    t.cancel()

async def c2():
    t = asyncio.Task(tf('c2'))
    await l.run_in_executor(None, sync_cpu_bound)
    t.cancel()

@asyncio.coroutine
def tf(name):
    c = 0
    try:
        while True:
            c += 1
            yield
    except asyncio.CancelledError:
        print(f'[debug={l.get_debug()}] count for {name}: {c}')
        raise


l = asyncio.new_event_loop()

for debug in [False, True]:
    l.set_debug(debug)
    l.run_until_complete(c0())
    l.run_until_complete(c1())
    l.run_until_complete(c2())