I'm trying to do something periodically and this would be on the millisec level precision.
However for some reason I could not achieve precise timing in a task.
Below example shows that a simple sleep randomly awakes with a jitter between 0.1-20.0ms I haven't hystogrammed the distribution but it seems to be mostly 19-20ms.

Any way to achieve better timings with asyncio?

async def test_task():
    while True:
        ts_now = time.time();
        await asyncio.sleep(1.000);
        print("{}".format((time.time()-ts_now)*1000.0));

if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    loop.create_task(thread_main())
    loop.run_forever()

correction:
a) of course i meant loop.create_task(test_task())

b) when using threading the sleep returns every 1000ms when going lower 10-15ms is also spot on. (I wanted to use threading in my app but one library - websocket - is asyncio based thus i'm stuck with asyncio)

asyncio provides the preemptive concurrency, not the real-time one.
It means that the exact time of task switches depends on other tasks' execution and can vary by design.

Sorry, the jitter is unavoidable.