Speed up coroutine creation ?

[kumaraditya303]

Python version - Python 3.11.0a3+

Script:

import timeit
async def coro():pass
def gen():
    yield

print("Coroutine:",timeit.timeit(lambda:coro(), number=1000000))
print("Generator:",timeit.timeit(lambda:gen(), number=1000000))

Results:

Running Debug|x64 interpreter...
<timeit-src>:6: RuntimeWarning: coroutine 'coro' was never awaited
RuntimeWarning: Enable tracemalloc to get the object allocation traceback
Coroutine: 10.316932699999597
Generator: 1.845993200004159

Coroutine creation is atleast 5.7x slower than a generator which is very slow considering that in asyncio coroutine are created at very high rate.

Further investigation revealed that most of the slowness is due to tracking of coroutine if it was awaited or not:

Script:

import timeit
async def coro():pass
def gen():
    yield

print("Coroutine:",timeit.timeit(lambda:coro().close(), number=1000000))
print("Generator:",timeit.timeit(lambda:gen(), number=1000000))

Results:

Coroutine: 1.8880774999997811
Generator: 1.7808137999963947

If the created coroutine is closed so that its tracking feature does not track it then it is margin of error slower than generator, revealing that tracking coroutine is slowing it down.

[gvanrossum]

Can you test again, adding await or next()?

[asvetlov]

Please clarify, did you measure coroutine creation time or a time of raising RuntimeWarning?

Looing on the script, I suspect the second.
A well-written program never emits such warnings.

[kumaraditya303]

Yes it seems like it is more about coroutine tracking than coroutine creation, I'll try to come up with another script which is solely about coroutine creation.