golang/go#11343

2096128.png

2096129.png

main.go

package main

import (
	"flag"
	"io"
	"io/ioutil"
	"log"
	"os"
	"runtime"
	"runtime/pprof"
)

var fSize = flag.Int64("size", 0, "Number of zeroes to read.")

func run() (err error) {
	// Collect a detailed heap profile, writing it out when we're finished.
	runtime.MemProfileRate = 1

	profile, err := os.Create("/tmp/mem.pprof")
	if err != nil {
		return
	}

	defer profile.Close()
	defer func() {
		pprof.Lookup("heap").WriteTo(profile, 1)
	}()

	// Read some zeroes.
	zero, err := os.Open("/dev/zero")
	if err != nil {
		return
	}

	defer zero.Close()

	_, err = ioutil.ReadAll(io.LimitReader(zero, *fSize))
	if err != nil {
		return
	}

	// Make some other allocations.
	for i := 0; i < 1<<10; i++ {
		io.MultiWriter(ioutil.Discard, ioutil.Discard)
	}

	return
}

func main() {
	flag.Parse()

	// Run.
	err := run()
	if err != nil {
		log.Fatal(err)
	}
}