go-bench

main_test.go

// benchmarking two flavors of logging
//
// run with `go test -benchmem -bench=.`
//
// Example output:
// ----------------------------------------------------------
// goos: darwin
// goarch: arm64
// pkg: go-benchmarks
// BenchmarkLogPlain-10          3548698          332.0 ns/op            64 B/op        2 allocs/op
// BenchmarkLogExtra-10          1528564          780.5 ns/op           376 B/op        6 allocs/op
// PASS
// ok      go-benchmarks   3.603s
// ----------------------------------------------------------
package main

import (
	"fmt"
	"log"
	"os"
	"runtime"
	"testing"
)

func logPlain(msg string) {
	fmt.Println("some fairly long log message asldkasldkasjdl asda dadasdasdakasdlkasldkasldka", msg)
}

func logExtra(msg string) {
	pc, _, _, _ := runtime.Caller(1)
	fmt.Println(fmt.Sprintf("%s: some fairly long log message", runtime.FuncForPC(pc).Name()))
}

func BenchmarkLogPlain(b *testing.B) {
	defer quiet()()

	for i := 0; i < b.N; i++ {
		logPlain("test")
	}
}

func BenchmarkLogExtra(b *testing.B) {
	defer quiet()()

	for i := 0; i < b.N; i++ {
		logExtra("test")
	}
}

// https://stackoverflow.com/a/58720235/9823455
func quiet() func() {
	null, _ := os.Open(os.DevNull)
	sout := os.Stdout
	serr := os.Stderr
	os.Stdout = null
	os.Stderr = null
	log.SetOutput(null)
	return func() {
		defer null.Close()
		os.Stdout = sout
		os.Stderr = serr
		log.SetOutput(os.Stderr)
	}
}