string_building_benchmark.go

package main

import (
	"bytes"
	"fmt"
	"strconv"
	"sync"
	"testing"
)

func BenchmarkSprintf(b *testing.B) {
	for i := 0; i < b.N; i++ {
		_ = fmt.Sprintf("[%d] %s <%s>\n", i, "Sergio", "sergio@example.com")
	}
}

func BenchmarkBuffer(b *testing.B) {
	pool := sync.Pool{
		New: func() interface{} {
			return &bytes.Buffer{}
		},
	}
	for i := 0; i < b.N; i++ {
		buf := pool.Get().(*bytes.Buffer)

		buf.WriteString("[")
		buf.WriteString(strconv.Itoa(i))
		buf.WriteString("] ")
		buf.WriteString("Sergio")
		buf.WriteString(" <")
		buf.WriteString("sergio@example.com")
		buf.WriteString(">\n")

		buf.Reset()
		pool.Put(buf)
	}
}

//BenchmarkSprintf-8   	10000000	       184 ns/op	      56 B/op	       2 allocs/op
//BenchmarkBuffer-8    	20000000	        93.6 ns/op	       7 B/op	       0 allocs/op