gistfile1.txt

/*
jed@thevm:~/go/src/bench/copy$ go test --test.bench=. --test.benchtime=10s .
testing: warning: no tests to run
PASS
BenchmarkAppendNil	   50000	    627957 ns/op
BenchmarkMakeCopy	   50000	    627037 ns/op
BenchmarkAppendMake	   50000	    611550 ns/op'

And using a 1k 's'...
BenchmarkAppendNil	50000000	       563 ns/op
BenchmarkMakeCopy	50000000	       579 ns/op
BenchmarkAppendMake	50000000	       529 ns/op


*/

package copy_bench

import (
	"testing"
)

var s = make([]byte, 1024*1024*5)

func BenchmarkAppendNil(b *testing.B) {
	for i := 0; i < b.N; i++ {
		_ = append([]byte(nil), s...)
	}
}

func BenchmarkMakeCopy(b *testing.B) {
	for i := 0; i < b.N; i++ {
		n := make([]byte, len(s))
		copy(n, s)
	}
}

func BenchmarkAppendMake(b *testing.B) {
	for i:=0; i < b.N; i++{
		_ = append(make([]byte, 0, len(s)), s...)
	}
}