bench_prefix.go

package prefix_access

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

func hasPrefix(buf []byte, prefix []byte) bool {
	return buf[0] == prefix[0] && buf[1] == prefix[1]
}

func hasPrefix2(buf []byte, prefix uint16) bool {
	return binary.BigEndian.Uint16(buf) == prefix
}

func BenchmarkAccess(b *testing.B) {
	prefix := []byte("tr")
	buf := []byte("trabc")
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		hasPrefix(buf, prefix)
	}
}

func BenchmarkAccess2(b *testing.B) {
	prefix := binary.BigEndian.Uint16([]byte("tr"))
	buf := []byte("trabc")
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		hasPrefix2(buf, prefix)
	}
}

func BenchmarkHasPrefix(b *testing.B) {
	prefix := []byte("tr")
	b.ResetTimer()
	buf := []byte("trabc")
	for i := 0; i < b.N; i++ {
		bytes.HasPrefix(buf, prefix)
	}
}

gistfile1.txt

goos: darwin
goarch: amd64
BenchmarkAccess-4      	2000000000	         0.81 ns/op
BenchmarkAccess2-4     	2000000000	         0.27 ns/op
BenchmarkHasPrefix-4   	300000000	         5.66 ns/op

goos: linux
goarch: amd64
BenchmarkAccess-40       	2000000000	         0.97 ns/op
BenchmarkAccess2-40      	2000000000	         0.33 ns/op
BenchmarkHasPrefix-40    	200000000	         7.34 ns/op