Inside Go Channels: Buffers, Locks, and the Runtime Memory Model

Go channels are a core concurrency feature designed to safely coordinate goroutines without manual locks. Beneath their simple syntax lies a complex runtime system: channels are built on hchan structs with buffers, queues, and locks; sudog structures represent blocked goroutines; and the Go scheduler integrates tightly to park and wake goroutines efficiently. From direct stack copies in unbuffered sends to broadcast semantics when closing channels, every detail ensures correctness and performance. This deep dive explains how channels embody CSP principles, why they’re safer than shared memory, and how understanding their internals helps developers write better concurrent Go programs.