pprof-test.go

package main

import (
	"net"
	"net/http"
	_ "net/http/pprof"
)

const host = "localhost:4242"

var sink int

// Takes a few ms CPU time
func doSomething() {
	for i := 0; i < 1000000; i++ {
		sink += i
	}
}

// Opens a UDP listener and ignores any data
func udpSink() {
	laddr, err := net.ResolveUDPAddr("udp", host)
	if err != nil {
		panic(err)
	}
	l, err := net.ListenUDP("udp", laddr)
	if err != nil {
		panic(err)
	}
	buf := make([]byte, 1000)
	for {
		_, _, err := l.ReadFromUDP(buf)
		if err != nil {
			panic(err)
		}
	}
}

func main() {
	go http.ListenAndServe("localhost:8080", nil)
	go udpSink()

	addr, err := net.ResolveUDPAddr("udp", host)
	if err != nil {
		panic(err)
	}
	c, err := net.DialUDP("udp", nil, addr)
	if err != nil {
		panic(err)
	}

	buf := make([]byte, 1000)
	for {
		// First, send
		_, err = c.Write(buf)
		if err != nil {
			panic(err)
		}
		// then, occupy CPU
		doSomething()
	}
}