详解Go 并发

// 串行执行
func SerializeRun() {
	start := time.Now()
	xx := []int{1, 2, 3}
	yy := []int{100, 200, 300}
	for _, x := range xx {
		for _, y := range yy {
			abc(x, y)
		}
	}
	fmt.Printf("串行执行总时间:%s\n", time.Since(start))
}

func abc(x, y int) {
	time.Sleep(time.Second * 1)
	fmt.Printf("x:%d, y:%d\n", x, y)
}

// 单并行执行
func SingleConcurrenceRun() {
	start := time.Now()
	xx := []int{1, 2, 3}
	yy := []int{100, 200, 300}
	for _, x := range xx {
		wgg := sync.WaitGroup{}
		for _, y := range yy {
			wgg.Add(1)
			go func(x, y int) {
				defer wgg.Done()
				abc(x, y)
			}(x, y)
		}
		wgg.Wait()
	}
	fmt.Printf("单并行执行总时间:%s\n", time.Since(start))
}
func abc(x, y int) {
	time.Sleep(time.Second * 1)
	fmt.Printf("x:%d, y:%d\n", x, y)
}

// 嵌套执行
func NestConcurrenceRun() {
	xx := []int{1, 2, 3}
	yy := []int{100, 200, 300}
	start := time.Now()
	wgg := sync.WaitGroup{}
	for _, x := range xx {
		wgg.Add(1)
		go func(x int) {
			wg := sync.WaitGroup{}
			for _, y := range yy {
				wg.Add(1)
				go func(x, y int) {
					defer wg.Done()
					abc(x, y)
				}(x, y)
			}
			wg.Wait()
			wgg.Done()
		}(x)
	}
	wgg.Wait()
	fmt.Printf("嵌套并发执行总时间:%s\n", time.Since(start))
}
func abc(x, y int) {
	time.Sleep(time.Second * 1)
	fmt.Printf("x:%d, y:%d\n", x, y)
}