seniorRust

How would you design a Rust async runtime from scratch?

Updated May 24, 2026

Short answer

A Rust async runtime requires an executor, task scheduler, reactor (I/O driver), and a wake-up mechanism via Waker.

Deep explanation

A full runtime consists of: (1) task queue storing Futures, (2) executor polling tasks, (3) reactor handling OS I/O events (epoll/kqueue/IOCP), (4) Waker system for rescheduling tasks. The executor continuously polls ready tasks while the reactor signals readiness via events.

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