Golang XOR performance for 8/64 bytes long integers

result.txt

$ go test -bench .
PASS
Benchmark8	 1000000	      1093 ns/op	 936.69 MB/s
Benchmark64	20000000	       134 ns/op	7603.74 MB/s
ok  	_/private/tmp/x	3.944s

xor_test.go

package x

import (
	"bytes"
	"encoding/binary"
	"testing"
)

func TestLen(t *testing.T) {
	if len(A) != len(B) {
		t.Fatal("length of a and b differs")
	}
}

func Benchmark8(b *testing.B) {
	for i := 0; i < b.N; i++ {
		for j := range A {
			_ = A[j] ^ B[j]
		}
	}
	b.SetBytes(int64(len(A)))
}

func Benchmark64(b *testing.B) {
	var au, bu []uint64
	au = make([]uint64, len(A)/8)
	bu = make([]uint64, len(B)/8)
	if err := binary.Read(bytes.NewReader(A), binary.LittleEndian, au); err != nil {
		b.Fatal(err)
	}
	if err := binary.Read(bytes.NewReader(B), binary.LittleEndian, bu); err != nil {
		b.Fatal(err)
	}
	for i := 0; i < b.N; i++ {
		for j := range au {
			_ = au[j] ^ bu[j]
		}
	}
	b.SetBytes(int64(len(A)))
}

var A, B []byte

func init() {
	A = make([]byte, 1024)
	B = make([]byte, 1024)
}