asyncio.gather is quite slow

gistfile1.py

"""
asyncio.gather might be getting faster:

See https://github.com/python/cpython/pull/4913
"""

import os
NUM=int(os.environ.get('NUM', 1))


def do_something_sync(num):
    return num + 1

async def do_something_async(num):
    return num + 1


#######


def test_sync():
    for x in range(1, 100000):
        do_something_sync(x)


async def test_asyncio_gather():
    for x in range(1, 100000):
        await asyncio.gather(
            do_something_async(x)
        )


async def test_async_direct():
    for x in range(1, 100000):
        await do_something_async(x)


async def test_trio_nursery():
    for x in range(1, 100000):
        async with trio.open_nursery() as n:
            n.start_soon(do_something_async, x)


#######


if __name__ == '__main__':
    import timeit, sys
    mode = sys.argv[1]

    if mode == 'sync':
        print(timeit.timeit("test_sync()", setup="from __main__ import test_sync", number=NUM))

    if mode == 'asyncio':
        import asyncio
        def main_async():
            asyncio.get_event_loop().run_until_complete(test_async_direct())
        print(timeit.timeit("main_async()", setup="from __main__ import main_async", number=NUM))

    if mode == 'asyncio-gather':
        import asyncio
        def main_gather():
            asyncio.get_event_loop().run_until_complete(test_asyncio_gather())
        print(timeit.timeit("main_gather()", setup="from __main__ import main_gather", number=NUM))

    if mode == 'trio':
        import trio
        def main_trio():
            trio.run(test_async_direct)
        print(timeit.timeit("main_trio()", setup="from __main__ import main_trio", number=NUM))

    if mode == 'trio-nursery':
        import trio
        def main_trio_nursery():
            trio.run(test_trio_nursery)
        print(timeit.timeit("main_trio_nursery()", setup="from __main__ import main_trio_nursery", number=NUM))


"""
Python 3.6.3, trio==0.4.0 (git checkout)

$ python speedtest.py sync
0.013295362994540483

$ python speedtest.py async
0.024491631003911607

$ python speedtest.py asyncio-gather
3.644775936001679

$ python speedtest.py trio
0.02168167599302251

$ NUM=1 python speedtest.py trio-nursery
9.267848733012215


Approximate number of calls (NUM set to this value) to copmlete in 1s.
This is ignoring the range loop, so it includes the cost of setting up the event loop,
which is the reason why trio is so slow.

- sync: 7000.000
- asyncio: 40.000
- asyncio-gather: 16.000
- trio: 1200    (this is probably ac
- trio-nursery: 1100
"""