How to start coroutine in golang

Essentially, goroutine is a coroutine. The difference is that Golang encapsulates and processes goroutine scheduling in many aspects such as runtime and system calls. When encountering long-term execution or system calls. (Recommended learning: go)

will actively transfer the CPU (P) of the current goroutine so that other goroutines can be scheduled and executed. That is, Golang supports coroutines from the language level. .

One of the major features of Golang is that it natively supports coroutines from the language level. You can create a coroutine by adding the go keyword in front of a function or method.

Comparison of other aspects

Memory consumption

Each goroutine (coroutine) occupies memory by default There are far fewer threads than Java and C.

goroutine: 2KB

Thread: 8MB

Thread and goroutine switching scheduling overhead

Thread/goroutine switching overhead, Goroutine is far smaller than threads

Threads: involve mode switching (switching from user mode to kernel mode), 16 registers, PC, SP... and other register refreshes, etc.

goroutine: only three register value modifications - PC/SP/DX.

We know that coroutine (coroutine) is a lightweight thread implementation in the Go language. Managed by the Go runtime.

Add the go keyword before a function call, and the call will be executed concurrently in a new goroutine. When the called function returns, this goroutine also ends automatically. It should be noted that if this function has a return value, the return value will be discarded.

First look at the following program code:

func Add(x, y int) {
    z := x + y
    fmt.Println(z)
}
func main() {
    for i:=0; i<10; i++ {
        go Add(i, i)
    }
}

When you execute the above code, you will find that nothing is printed on the screen and the program exits.

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