[QUESTION] about qps

Description

The simple get ‘hello world’ server crashed when I send more than 510 requests in a second to the fastAPI.

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return "Hello World"

How to improve qps for it?

I‘ve checked and can’t find an effective way in questionhttps://github.com/tiangolo/fastapi/issues/603 or any other issues.

My environments: win10 1903 Python 3.7.5 64bit fastapi 0.52.0 uvicorn 0.11.3

used module grequests to send the requests.

import grequests, time, collections

def qps_test(url, N):
    start_time = time.time()
    res_list = grequests.map([
        grequests.get(url) 
        for _ in range(N)
    ])
    print(f'time: {time.time() - start_time}\nstatue_code:')
    print('\n'.join(
        f'{k}: {v}'
        for k, v in collections.Counter(
            res is None and 'LOST' or res.status_code
            for res in res_list
        ).items()
    ))

if __name__ == '__main__':
    qps_test('http://127.0.0.1:8000/', 500)
    # qps_test('http://127.0.0.1:8000/', 511) #crashed

uvicorn main:app --reload run in cmd (follow the docs). and i also tried uvicorn main:app , the same.

error message:

Process SpawnProcess-1: Traceback (most recent call last): File "d:\python37\lib\multiprocessing\process.py", line 297, in _bootstrap self.run() File "d:\python37\lib\multiprocessing\process.py", line 99, in run self._target(*self._args, **self._kwargs) File "d:\python37\lib\site-packages\uvicorn\subprocess.py", line 61, in subprocess_started target(sockets=sockets) File "d:\python37\lib\site-packages\uvicorn\main.py", line 382, in run loop.run_until_complete(self.serve(sockets=sockets)) File "d:\python37\lib\asyncio\base_events.py", line 566, in run_until_complete self.run_forever() File "d:\python37\lib\asyncio\base_events.py", line 534, in run_forever self._run_once() File "d:\python37\lib\asyncio\base_events.py", line 1735, in _run_once event_list = self._selector.select(timeout) File "d:\python37\lib\selectors.py", line 323, in select r, w, _ = self._select(self._readers, self._writers, [], timeout) File "d:\python37\lib\selectors.py", line 314, in _select r, w, x = select.select(r, w, w, timeout) ValueError: too many file descriptors in select()

[lithbitren]

www.v2ex.com/t/653100

fixed it.

from asyncio import ProactorEventLoop, set_event_loop, ProactorEventLoop, get_event_loop
from uvicorn import Config, Server
if __name__ == "__main__":
    set_event_loop(ProactorEventLoop())
    server = Server(config=Config(app=app))
    get_event_loop().run_until_complete(server.serve())

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