Expert · Module 10 · Lesson 6 of 12

Asynchronous Event Integration: Cooperative I/O with epoll and timerfd

Integrate Linux epoll and timerfd into a cooperative coroutine scheduler, transform blocking network and sleep calls into non-blocking yields, and achieve synchronous-style asynchronous I/O.

ProAbout 16 minutes

By the end you can

Transform blocking socket I/O into non-blocking cooperative fiber suspension on EAGAIN
Multiplex waiting fibers using Linux epoll event notification and EPOLLONESHOT
Implement non-blocking fiber sleep routines using Linux timerfd descriptors
Architect an integrated scheduler event loop balancing ready queues with epoll_wait

Builds on Coroutine Lifecycles, Trampolines, and State Machines.

01 · A question first

If a single coroutine calls a standard blocking read() or sleep(), the entire operating system thread freezes, halting thousands of co-located fibers. How can we make non-blocking I/O and timers feel like synchronous C code while keeping the event loop moving at line rate?

Make a guess before you read on.

02 · The idea

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What's inside

Start with the problem
How the idea works
Complete Working Implementation: The Asynchronous Fiber Engine
Why it is correct
What it costs
Pitfalls and variations
Where it is used