demonstrating the performance of `asyncio.wait`

asyncio_wait_test.py

import asyncio
from statistics import mean, stdev
from time import time

from aiohttp import ClientSession

request_count = 1500
url = 'https://requestb.in/1fz8k451'


async def main(loop, use_first_complete=False):
    print(f'using FIRST_COMPLETED: {use_first_complete}')
    start_time = time()
    async with ClientSession(loop=loop) as session:
        async def run(v, _create_time):
            _start_time = time()
            async with session.get(url) as r:
                assert r.status == 200
            wait, request = _start_time - _create_time, time() - _start_time
            # print(f'{v:>5} wait: {wait:0.3f}s, request: {request:0.3f}s')
            return wait, request

        pending_tasks = {loop.create_task(run(i, time())) for i in range(request_count)}
        if use_first_complete:
            complete_tasks = set()
            while pending_tasks:
                done, pending_tasks = await asyncio.wait(pending_tasks, loop=loop, return_when=asyncio.FIRST_COMPLETED)
                complete_tasks.update(done)
        else:
            complete_tasks, pending_tasks = await asyncio.wait(pending_tasks, loop=loop)
            assert not pending_tasks

    time_taken = time() - start_time
    print(f'total time taken {time_taken:0.2f}')
    results = [t.result() for t in complete_tasks]
    wait_times, request_times = zip(*results)
    print(f'wait times:    mean {mean(wait_times):0.3f}s, stdev {stdev(wait_times):0.3f}s')
    print(f'request times: mean {mean(request_times):0.3f}s, stdev {stdev(request_times):0.3f}s')


loop = asyncio.get_event_loop()
loop.run_until_complete(main(loop, use_first_complete=False))

monitor-screenshot.png

results.txt

➤ python perf.py 
using FIRST_COMPLETED: False
total time taken 4.07
wait times:    mean 0.136s, stdev 0.059s
request times: mean 1.824s, stdev 0.947s
➤ python perf.py 
using FIRST_COMPLETED: False
total time taken 5.05
wait times:    mean 0.135s, stdev 0.057s
request times: mean 2.172s, stdev 1.125s
➤ python perf.py 
using FIRST_COMPLETED: False
total time taken 5.98
wait times:    mean 0.142s, stdev 0.060s
request times: mean 2.450s, stdev 1.334s

➤ python perf.py 
using FIRST_COMPLETED: True
total time taken 47.46
wait times:    mean 0.132s, stdev 0.058s
request times: mean 10.103s, stdev 8.111s
➤ python perf.py 
using FIRST_COMPLETED: True
total time taken 27.69
wait times:    mean 0.138s, stdev 0.057s
request times: mean 8.536s, stdev 7.914s
➤ python perf.py 
using FIRST_COMPLETED: True
total time taken 18.18
wait times:    mean 0.139s, stdev 0.059s
request times: mean 5.934s, stdev 5.327s