What is the GMP model in Go?

Question

Accepted Answer

**GMP** — Goroutine, Machine, Processor. Go's scheduler model.

**G (Goroutine):**
- Lightweight thread.
- Has stack, instruction pointer.
- Managed by Go.

**M (Machine):**
- OS thread.
- Executes goroutines.
- Limited by OS.

**P (Processor):
- Logical processor.
- Has local run queue.
- GOMAXPROCS controls count.

```go
// Number of processors
fmt.Println(runtime.GOMAXPROCS(0))  // Default: CPU cores
```

**How it works:**
- P processors run M threads.
- Each P has local queue of G goroutines.
- When P's queue empty, steals from other P.
- M can block without blocking P.

**Benefits:**
- Efficient parallelism.
- No global lock.
- Work stealing.

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