2.14 goroutine

1. What Is a goroutine

• Programs, processes, and threads.md (related note is not yet published)
• A user thread implemented by the Go language
• Compared with threads, goroutines have:
  • Creation, destruction, and switching: all completed in user space without entering the kernel
  • Memory usage: the default stack size is 2K and can dynamically grow and shrink

2. goroutine Usage

2.1. Create a Goroutine

func TestGoroutine1(t *testing.T) {
	go func(x, y, z int) {
		time.Sleep(time.Second * 1)
		fmt.Println(x + y + z)
	}(1, 2, 3)
	time.Sleep(time.Minute * 5)

}

• go f(x, y, z) starts a new goroutine to run the function f(x, y, z)
  • The function f and the values of variables x, y, and z are evaluated in the original goroutine; only the execution of function f happens in the new goroutine
  • The new goroutine creates a new stack

2.2. Goroutine Pool

Goroutine Pool

3. goroutine Implementation

func TestGoroutine1(t *testing.T) {
	go func(x, y, z int) {
		time.Sleep(time.Second * 1)
		fmt.Println(x + y + z)
	}(1, 2, 3)
	time.Sleep(time.Minute * 5)

}

• go tool compile -S Goroutine function call go f(1, 2, 3):

0x0024 00036 (goroutine1_test.go:10)	PCDATA	$0, $0
0x0024 00036 (goroutine1_test.go:10)	 PCDATA	$1, $0
0x0024 00036 (goroutine1_test.go:10)	MOVL	$24, (SP)
0x002b 00043 (goroutine1_test.go:10)	PCDATA	$0, $1
0x002b 00043 (goroutine1_test.go:10)	LEAQ	"".TestGoroutine1.func1·f(SB), AX
0x0032 00050 (goroutine1_test.go:10)	PCDATA	$0, $0
0x0032 00050 (goroutine1_test.go:10)	MOVQ	AX, 8(SP)
0x0037 00055 (goroutine1_test.go:10)	MOVQ	$1, 16(SP)
0x0040 00064 (goroutine1_test.go:10)	MOVQ	$2, 24(SP)
0x0049 00073 (goroutine1_test.go:10)	MOVQ	$3, 32(SP)
0x0052 00082 (goroutine1_test.go:10)	CALL	runtime.newproc(SB)

It can be seen that it calls CALL runtime.newproc(SB). That is, go f(args) is equivalent to runtime.newproc(size, f, args).

4. goroutine Scheduling

GMP.md

5. References

• Overview of the Go Goroutine Scheduler (11) - Abo Zhang - cnblogs