Am 19.04.2016 um 23:02 schrieb Imran Geriskovan:
A) Python threads are not real threads. It multiplexes "Python Threads"
on a single OS thread. (Guido, can you correct me if I'm wrong,
and can you provide some info on multiplexing/context switching of
"Python Threads"?)
Sorry, you are wrong. Python threads map 1:1 to OS threads. They are as
real as threads come (the GIL notwithstanding).
Ok then. Just to confirm for cpython:
- Among these OS threads, only one thread can run at a time due to GIL.
A thread releases GIL (thus allow any other thread began execution)
when waiting for blocking I/O. (http://www.dabeaz.com/python/GIL.pdf)
This is similar to what we do in asyncio with awaits.
Thus, multi-threaded I/O is the next best thing if we do not use asyncio.
Then the question is still this: Which one is cheaper?
Thread overheads or asyncio overheads.
The overhead of cooperative multitasking is smaller, but for maximum
performance you need to combine that with preemptive multitasking
because to saturate modern hardware, you need high IO concurrency
(I am leaving out stuff like Linux AIO in this discussion)
