Find out the relationship between coredns response and frequency

main.go

package main

import (
	"fmt"
	"os"
	"os/exec"
	"strings"
	"sync"
	"time"
)

func main() {
	record(1)
	record(10)
	record(100)
	record(500)
	record(1000)
	record(1250)
	record(1500)
	record(1750)
	record(2000)
	record(2250)
	record(2500)
}

func record(count float64) {
	start := time.Now()
	wg := sync.WaitGroup{}
	for i := 0; i < int(count); i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			execDig()
		}()
	}
	wg.Wait()
	end := time.Now()
	diff := (end.Sub(start)).Seconds()

	fmt.Printf("------------------------------------\n")
	fmt.Printf("Number of requests:%d\n", int(count))
	fmt.Printf("Total response(sec):%f\n", diff)
	fmt.Printf("Average response(sec):%f\n", diff/count)
	execTop()
}

func execTop() {
	out,err := exec.Command("./top.sh").Output()
	if err != nil {
		fmt.Println(err.Error())
		os.Exit(1)
	}
	fmt.Printf("top command: \n%s", string(out))
}

func execDig() {
	args := strings.Fields("dig @127.0.0.1 -p 53 www.example.com")
	_, err := exec.Command("dig", args...).Output()
	if err != nil {
		fmt.Println(err.Error())
		os.Exit(1)
	}
}

top.sh

#!/bin/sh

top -l 1 -s 0 | grep coredns