circuitpython/tests/extmod/uasyncio_fair.py
Damien George 55c76eaac1 extmod/uasyncio: Truncate negative sleeps to 0.
Otherwise a task that continuously awaits on a large negative sleep can
monopolise the scheduler (because its wake time is always less than
everything else in the pairing heap).

Signed-off-by: Damien George <damien@micropython.org>
2020-08-22 12:17:06 +10:00

34 lines
656 B
Python

# Test fairness of scheduler
try:
import uasyncio as asyncio
except ImportError:
try:
import asyncio
except ImportError:
print("SKIP")
raise SystemExit
async def task(id, t):
print("task start", id)
while True:
if t > 0:
print("task work", id)
await asyncio.sleep(t)
async def main():
t1 = asyncio.create_task(task(1, -0.01))
t2 = asyncio.create_task(task(2, 0.1))
t3 = asyncio.create_task(task(3, 0.2))
t3 = asyncio.create_task(task(4, -100))
await asyncio.sleep(0.5)
t1.cancel()
t2.cancel()
t3.cancel()
print("finish")
asyncio.run(main())