interface_benchmark_test.go

package main

import "testing"

type I interface {
	Hello()
}

type A struct {}
func (a A) Hello() {}

func BenchmarkStruct(b *testing.B) {
	var a = A{}
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		a.Hello()
	}
}

func BenchmarkInterface(b *testing.B) {
	var a I = A{}
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		a.Hello()
	}
}
func BenchmarkEmptyInterface(b *testing.B) {
	var a = A{}
	var ai interface{} = a
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		if x, ok := ai.(A); ok  {
			x.Hello()
		}
	}
}

/*
BenchmarkStruct-8           	2000000000	         0.41 ns/op
BenchmarkInterface-8        	500000000	         3.39 ns/op
BenchmarkEmptyInterface-8   	2000000000	         0.36 ns/op
*/