runtime 包，定义了协程管理相关的 API

runtime.Gosched()

package mainimport ("fmt""runtime"
)func main() {go func() {for i := 0; i <= 5; i++ {fmt.Println(i)}}()// 让出当前CPU给其他协程runtime.Gosched()fmt.Println("end...")
}

runtime.Goexit()

package mainimport ("fmt""runtime""time"
)func show() {for i := 0; i <= 5; i++ {if i > 3 {// 退出当前协程runtime.Goexit()}fmt.Println(i)}
}func main() {go show()// 主协程睡眠1stime.Sleep(time.Second)fmt.Println("end...")
}

runtime.GOMAXPROCS()

package mainimport ("fmt""runtime""time"
)func funcA() {for i := 0; i < 5; i++ {fmt.Printf("funcA: %v \n", i)time.Sleep(time.Millisecond * 100)}
}func funcB() {for i := 0; i < 5; i++ {fmt.Printf("funcB: %v \n", i)time.Sleep(time.Millisecond * 100)}
}func main() {fmt.Printf("CPU nums: %v \n", runtime.NumCPU())// 设置最大CPU核心数runtime.GOMAXPROCS(1)go funcA()go funcB()// 主协程睡眠1stime.Sleep(time.Second)fmt.Println("end...")
}

Mutex 互斥锁实现同步

sync.Mutex

package mainimport ("fmt""sync""time"
)var count int
var wp sync.WaitGroup
var lock sync.Mutexfunc add() {defer wp.Done()// 加锁lock.Lock()count++fmt.Printf("add: %v \n", count)time.Sleep(time.Millisecond * 10)// 解锁lock.Unlock()
}func sub() {defer wp.Done()lock.Lock()count--fmt.Printf("sub: %v \n", count)time.Sleep(time.Millisecond * 100)lock.Unlock()
}func main() {for i := 0; i < 10; i++ {wp.Add(1)go add()wp.Add(1)go sub()}// 等待子协程执行完再执行主协程wp.Wait()fmt.Printf("count: %v \n", count)fmt.Println("end...")
}