uvloop may sleep less than `n` for asyncio.sleep(n)

Bug Description

When calling asyncio.sleep, uvloop sometimes sleeps for fractionally less then the requested sleep time. E.g. await asyncio.sleep(0.1) -> Sleeps for 0.0991.

Expected behavior

Should always sleep for at least the specified time.

Environment

• Operating System: Fedora 43
• Python Version: Python 3.13.12
• uvloop Version: 0.22.1

Steps to Reproduce

Run the following script and observe output:

import asyncio
import statistics
import time

async def main():
    sleep_times = []
    for _ in range(100):
        start_time = time.perf_counter()
        await asyncio.sleep(0.1)
        end_time = time.perf_counter()
        sleep_times.append(end_time - start_time)
    print(f"Min sleep time: {min(sleep_times):.4f} seconds")
    print(f"Max sleep time: {max(sleep_times):.4f} seconds")
    print(f"Average sleep time: {statistics.mean(sleep_times):.4f} seconds")

if __name__ == "__main__":
    print("With default asyncio event loop:")
    asyncio.run(main())
    print("With uvloop event loop:")
    import uvloop
    asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())
    asyncio.run(main())

Output:

With default asyncio event loop:
Min sleep time: 0.1001 seconds
Max sleep time: 0.1008 seconds
Average sleep time: 0.1002 seconds
With uvloop event loop:
Min sleep time: 0.0991 seconds
Max sleep time: 0.1011 seconds
Average sleep time: 0.1001 seconds

Commencez par exécuter la reproduction fournie avec la boucle asyncio par défaut et uvloop, puis suivez la manière dont uvloop gère les minuteurs de asyncio.sleep. Comparez la durée mesurée au délai demandé et ajoutez un test de régression pour la durée minimale de veille. C’est terminé lorsque asyncio.sleep(n) ne retourne pas avant que n se soit écoulé.