Question

I’ve got a thread that’s polling a piece of hardware.

while not hardware_is_ready():     pass process_data_from_hardware() 

But there are other threads (and processes!) that might have things to do. If so, I don’t want to burn up cpu checking the hardware every other instruction. It’s been a while since I’ve dealt with threading, and when I did it wasn’t Python, but I believe most threading libraries have a yield function or something that allows a thread to tell the scheduler ‘Give the other threads a chance.’

while not hardware_is_ready():     threading.yield()          # This function doesn't exist. process_data_from_hardware() 

But I can’t find any reference to something like this in the threading documentation. Python does have a yield statement, but I’m pretty sure that’s something else entirely (to do with generators).

What’s the correct thing to do here?

Answer 1

time.sleep(0) is sufficient to yield control — no need to use a positive epsilon. Indeed, time.sleep(0) MEANS ‘yield to whatever other thread may be ready’.