Golang: runtime.GOMAXPROCS 的设置问题。

老哥们，我把代码中的 runtime.GOMAXPROCS(1) 注释掉了，可是程序运行下来的时间根本没减少，这是为什么？
真是百思不得骑呐

package main

import (
	"fmt"
	"time"
	"runtime"
)

var quit chan int = make(chan int)

func loop() {
	for i := 0; i < 10000; i++ {
		fmt.Printf("%d\n ", i)
	}
	quit <- 0
}

func main() {
	fmt.Println(runtime.NumCPU())
	time.Sleep(time.Second)
	a := 500
	t1 := time.Now()
	runtime.GOMAXPROCS(1)  //单核跑和把这句话注释吊(使用默认 CPU 个数)跑下来时间没差，这是为什么？

	for i := 1; i <= a; i++ {
		go loop()
	}

	for i := 0; i < a; i++ {
		<-quit
	}
	elapsed := time.Since(t1)
	fmt.Println("运行时间：", elapsed)
}

// 下面是 GOMAXPROCS 的说明

// GOMAXPROCS sets the maximum number of CPUs that can be executing
// simultaneously and returns the previous setting. If n < 1, it does not
// change the current setting.
// The number of logical CPUs on the local machine can be queried with NumCPU.
// This call will go away when the scheduler improves.