get mcount from go

mcount.go

package main

import (
	"C"
	"fmt"
	"runtime"
    "runtime/debug"
	"time"
    "os/exec"
	_ "unsafe"
)

//go:linkname mcount runtime.mcount
func mcount() int32

func getGOMAXPROCS() int {
	return runtime.GOMAXPROCS(0)
}

func main() {
	//runtime.GOMAXPROCS(20)
	fmt.Printf("GOMAXPROCS is %d\n", getGOMAXPROCS())
    debug.SetMaxThreads(50)

	go func() {
		for {
			cnt := mcount()
			fmt.Println(cnt)
			time.Sleep(time.Second)
		}
	}()

	for i := 0; i < 100; i++ {
		go func() {
			cmd := exec.Command("sleep", "600")
			if err := cmd.Run(); err != nil {
                fmt.Println(err)
			}
		}()
        time.Sleep(time.Second)
	}

	c := make(chan int)
	<-c
}