What do you know about the goroutine scheduler in Go?

The goroutine scheduler in Go is an integrated runtime mechanism that manages the execution of lightweight threads — goroutines. It implements the M:N model, where M is the number of system threads (OS threads), and N is the number of goroutines. The scheduler distributes goroutines across system threads, ensuring concurrent execution without the need to create a separate OS thread for each goroutine.

Main components of the scheduler:

• G (goroutine) — a structure describing a goroutine.
• M (machine) — a system thread on which goroutines run.
• P (processor) — a logical processor that connects M and G, managing the queue of ready-to-run goroutines.

The scheduler uses queue management of goroutines, load balancing between P and M, and preemption mechanisms to fairly distribute CPU time among goroutines. This allows efficient use of system resources and supports high concurrency with minimal overhead.