go 计算函数执行时间

func measureFuncExecTime() func() {
    pc, _, _, _ := runtime.Caller(1)
    funcName := runtime.FuncForPC(pc).Name()
    start := time.Now().UnixNano()
    return func() {
        fmt.Printf("function %s exec cost %+v\n", funcName, time.Duration(time.Now().UnixNano()-start).String())
    }
}

func foo() {
    defer measureFuncExecTime()()
    for i := 1; i <= 10; i++ {
        time.Sleep(5 * time.Microsecond)
    }
}

func main() {
    foo()
}

输出：