How to distinguish a goroutine from a regular thread in the operating system?

A goroutine is a lightweight thread of execution managed by the Go runtime, not the operating system. Main differences:

• Lightweight: Goroutines use much less memory (usually a few kilobytes of stack), whereas system threads require megabytes.
• Scheduling: Goroutines are scheduled by the Go runtime (M:N scheduler), not the OS. This allows running thousands of goroutines on multiple system threads.
• Creation: Creating a goroutine is very cheap — just write go function(), whereas creating a system thread is more resource-intensive.

Example of creating a goroutine:

func sayHello() {
    fmt.Println("Hello from goroutine")
}

func main() {
    go sayHello() // starts a goroutine
    time.Sleep(time.Second) // wait for the goroutine to finish
}

Thus, goroutines are an abstraction over OS threads, optimized for concurrent programming in Go.