Named string error benchmark

errors_test.go

package errstr

import (
	"errors"
	"testing"
)

type ErrString string

func (es ErrString) Error() string {
	return string(es)
}

func String(msg string) error {
	return ErrString(msg)
}

type errPtrString string

func (e *errPtrString) Error() string {
	return string(*e)
}

func newErrPtrStr(msg string) error {
	return (*errPtrString)(&msg)
}


const comparisonStr = ErrString("some error")

var (
	comparisonStd = errors.New("some error")
	comparisonPtrStr = newErrPtrStr("some error")
)


//go:noinline
func givesStringError() error {
	return comparisonStr
}

//go:noinline
func givesPtrStringError() error {
	return comparisonPtrStr
}

//go:noinline
func givesStdError() error {
	return comparisonStd
}

func BenchmarkString(b *testing.B) {

	b.Run("== String", func(b *testing.B) {
		var err error = givesStringError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			compResult = err == comparisonStr
		}
	})

	b.Run("== std", func(b *testing.B) {
		var err error = givesStdError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			compResult = err == comparisonStd
		}
	})

	b.Run("errors.Is String", func(b *testing.B) {
		var err error = givesStringError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			compResult = errors.Is(err, comparisonStr)
		}
	})

	b.Run("errors.Is errPtrString", func(b *testing.B) {
		var err error = givesPtrStringError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			compResult = errors.Is(err, comparisonPtrStr)
		}
	})

	b.Run("errors.Is std", func(b *testing.B) {
		var err error = givesStdError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			compResult = errors.Is(err, comparisonStd)
		}
	})

	b.Run("Error method, String", func(b *testing.B) {
		var err error = givesStringError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			errorResult = err.Error()
		}
	})

	b.Run("Error method, errPtrString", func(b *testing.B) {
		var err error = givesPtrStringError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			errorResult = err.Error()
		}
	})

	b.Run("Error method, std", func(b *testing.B) {
		var err error = givesStdError()
		b.ResetTimer()
		for i := 0; i < b.N; i++ {
			errorResult = err.Error()
		}
	})
}


var compResult bool

var errorResult string

goos: darwin
goarch: amd64

BenchmarkString
BenchmarkString/==_String-12         	983822860	         1.05 ns/op
BenchmarkString/==_std-12            	445498966	         2.72 ns/op
BenchmarkString/errors.Is_String-12  	127660197	         9.54 ns/op
BenchmarkString/errors.Is_errPtrString-12         	174831999	         6.73 ns/op
BenchmarkString/errors.Is_std-12                  	177377359	         6.71 ns/op
BenchmarkString/Error_method,_String-12           	480092460	         2.46 ns/op
BenchmarkString/Error_method,_errPtrString-12     	574903143	         2.13 ns/op
BenchmarkString/Error_method,_std-12              	571575463	         2.12 ns/op

go test -bench=. -count=1 -gcflags '-N -l'

goos: darwin
goarch: amd64

BenchmarkString/==_String-12         	126991862	         9.45 ns/op
BenchmarkString/==_std-12            	288934968	         4.10 ns/op
BenchmarkString/errors.Is_String-12  	100000000	        10.6 ns/op
BenchmarkString/errors.Is_errPtrString-12         	169028432	         7.09 ns/op
BenchmarkString/errors.Is_std-12                  	169673967	         7.11 ns/op
BenchmarkString/Error_method,_String-12           	227530143	         5.27 ns/op
BenchmarkString/Error_method,_errPtrString-12     	292550673	         4.10 ns/op
BenchmarkString/Error_method,_std-12              	380578506	         3.25 ns/op