pprof_example.go

pprof_example.go

package main

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

var (
	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to this file")
	memprofile = flag.String("memprofile", "", "write memory profile to this file")
)

func main() {
	flag.Parse()
	if *cpuprofile != "" {
		cpuf, err := os.Create(*cpuprofile)
		if err != nil {
			log.Fatal(err)
		}
		pprof.StartCPUProfile(cpuf)
		defer cpuf.Close()
		defer pprof.StopCPUProfile()
	}

	// some code
	var ints []int
	sum := 0
	for i := range 1_000_000 {
		ints = append(ints, i)
		sum += i
	}

	// snapshot mem
	if *memprofile != "" {
		memf, err := os.Create(*memprofile)
		if err != nil {
			log.Fatal(err)
		}
		pprof.WriteHeapProfile(memf)
		memf.Close()
	}
}