epoll

But, I mean, even that one fast waiter has physical limits, right? As the restaurant expands to 10,000 tables, just scanning the entire room over and over has to get slow.

It does, which is why the book brings in Select.epoll.

Okay, to stretch the restaurant metaphor, ePoll is like having a maitre d hooked up to an electronic buzzer system.

Huh, yes.

They don't have to scan the room at all.

The tables just press a button when they need water, and the maitre d instantly gets a notification of exactly who needs service.

And the underlying mechanics of ePoll are really fascinating.

It's a Linux-specific feature that operates directly at the OS kernel level using event-driven interrupts.