Asynchronous processing is more efficient -- surely not?

[INADA Naoki]

I agree with you.

Async IO is more efficient than threading for **waiting** I/O.
When there are thousands of idle connections, async I/O is best idea.

On the other hand, async I/O uses more system calls for busy I/O.

For example, when building chat application which handles thousands
WebSocket connection and uses MySQL as backend, I recommend to
use asyncio for WebSocket, but threadpool for transaction.

Regards,