pprof CPU and Heap profiling

pprof_cpu_heap.go

package main

import (
	"os"
	"io/fs"
	"runtime"
	"runtime/pprof"
)

func profiling(function func()) {
	done := make(chan struct{})

	err := os.Mkdir("./pprof", fs.ModePerm)
	if err != nil {
		if !os.IsExist(err) {
			panic(err)
		}
	}

	cpuW, err := os.Create("./pprof/cpu.pb.gz")
	if err != nil {
		panic(err)
	}
	defer cpuW.Close()

	heapW, err := os.Create("./pprof/heap.pb.gz")
	if err != nil {
		panic(err)
	}
	defer heapW.Close()

	go func(done chan struct{}) {
		defer func() { done <- struct{}{} }()

		pprof.StartCPUProfile(cpuW)

		function()

		pprof.StopCPUProfile()
	}(done)

	runtime.GC()
	pprof.WriteHeapProfile(heapW)

	<-done
}

func main() {
	profiling(func() {
		sieveOfEratosthenes(100000000)
	})
}

// return list of primes less than N
func sieveOfEratosthenes(N int) (primes []int) {
	b := make([]bool, N)
	for i := 2; i < N; i++ {
		if b[i] {
			continue
		}
		primes = append(primes, i)
		for k := i * i; k < N; k += i {
			b[k] = true
		}
	}
	return
}