bytes.Buffer grow benchmarks

perf_test.go

package main

import (
	"bytes"
	"encoding/xml"
	"fmt"
	"html/template"
	"strings"
	"testing"
)

func BenchmarkBufferWrite(b *testing.B) {
	for _, size := range []int{1, 8, 16, 32, 64, 128, 1024, 4096} {
		for _, numparts := range []int{1, 4, 8, 16} {
			parts := make([]string, numparts)
			for i := range parts {
				parts[i] = strings.Repeat("a", size)
			}
			b.Run(fmt.Sprintf("len%d_x%d", size, numparts), func(b *testing.B) {
				for i := 0; i < b.N; i++ {
					var b bytes.Buffer
					for _, part := range parts {
						b.WriteString(part)
					}
					bytesSink = b.Bytes()
				}
			})
		}
	}
}

func BenchmarkXMLMarshal(b *testing.B) {
	type User struct {
		ID   int      `xml:"id"`
		Name string   `xml:"name"`
		Tags []string `xml:"tag"`
	}
	type Root struct {
		Users []User `xml:"user"`
	}

	tags := []string{"simple-tag", "new"}
	createRoot := func(numUsers int) *Root {
		root := &Root{}
		for i := 0; i < numUsers; i++ {
			u := User{
				ID:   i + 1,
				Name: fmt.Sprintf("user-%d", i),
			}
			if i%2 == 0 {
				u.Tags = tags
			}
			root.Users = append(root.Users, u)
		}
		return root
	}

	for _, numUsers := range []int{50, 100, 200, 400, 800} {
		b.Run(fmt.Sprintf("numElems%d", numUsers), func(b *testing.B) {
			root := createRoot(numUsers)
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				_, err := xml.Marshal(root)
				if err != nil {
					b.Fatal(err)
				}
			}
		})
	}
}

func BenchmarkHTMLEscape(b *testing.B) {
	inputs := []string{
		`short & simple`,
		`<div id="data" class="a b"><b></b></div>`,
		`with "quotes" and longer than the previous text`,
		`this text has "-quotes, < and > chars & it's also longer than any of the texts before`,
	}
	for _, repeat := range []int{1, 2, 4, 8, 16, 32, 128, 1024} {
		for i, data := range inputs {
			data = strings.Repeat(data, repeat)
			b.Run(fmt.Sprintf("input%dx%d_%dbytes", i, repeat, len(data)), func(b *testing.B) {
				for i := 0; i < b.N; i++ {
					stringSink = template.HTMLEscapeString(data)
				}
			})
		}
	}
}

func BenchmarkHTMLTemplate(b *testing.B) {
	makeDocument := func(numURLs int) (string, []string) {
		var b strings.Builder
		urls := make([]string, numURLs)
		for i := 0; i < numURLs; i++ {
			fmt.Fprintf(&b, `<a href="{{index .URLS %d}}"></a>`, i)
			urls[i] = fmt.Sprintf("https://google.com/search?q=golang how to avoid GC spikes free without sms attempt %d&sclient=superpro", i)
		}
		return b.String(), urls
	}

	for _, numURLs := range []int{50, 500} {
		doc, urls := makeDocument(numURLs)
		tmpl := template.Must(template.New("example").Parse(doc))
		var data = struct {
			URLS []string
		}{
			URLS: urls,
		}
		b.Run(fmt.Sprintf("numURLs%d", numURLs), func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				var buf bytes.Buffer
				if err := tmpl.Execute(&buf, data); err != nil {
					b.Fatal(err)
				}
			}
		})
	}
}

var stringSink string
var bytesSink []byte