Benchmarking Go Interfaces

bench_interfaces.go

package main

import (
  "testing"
)

func Nop() {
}

type Stupid interface {
	Nop()
}

type Lame struct {
}

func (l Lame) Nop() {
}

func BenchmarkNop(b *testing.B) {
	for i := 0; i < b.N; i++ {
		Nop()
	}
}

func BenchmarkMemberFunction(b *testing.B) {
	a := Lame{}
	for i := 0; i < b.N; i++ {
		a.Nop()
	}
}

func BenchmarkMemberFunctionWithStructPointer(b *testing.B) {
	a := &Lame{}
	for i := 0; i < b.N; i++ {
		a.Nop()
	}
}

func AcceptsStupid(s Stupid) {
	s.Nop()
}

func BenchmarkInterfaceFunction(b *testing.B) {
	a := Lame{}
	for i := 0; i < b.N; i++ {
		AcceptsStupid(a)
	}
}

func BenchmarkInterfaceFunctionWithCast(b *testing.B) {
	a := Lame{}
	for i := 0; i < b.N; i++ {
		AcceptsStupid(Stupid(a))
	}
}

func BenchmarkInterfaceFunctionWithCastSaved(b *testing.B) {
	a := Lame{}
	c := Stupid(a)
	for i := 0; i < b.N; i++ {
		AcceptsStupid(c)
	}
}

func BenchmarkInterfaceFunctionWithTypeAssert(b *testing.B) {
	a := Lame{}
	c := Stupid(a).(Stupid)
	for i := 0; i < b.N; i++ {
		c.Nop()
	}
}

/*
---Results---
BenchmarkNop  2000000000	         1.28 ns/op
BenchmarkMemberFunction	2000000000	         1.92 ns/op
BenchmarkMemberFunctionWithStructPointer	2000000000	         1.45 ns/op
BenchmarkInterfaceFunction	50000000	        32.0 ns/op
BenchmarkInterfaceFunctionWithCast	50000000	        32.0 ns/op
BenchmarkInterfaceFunctionWithCastSaved	100000000	        12.7 ns/op
BenchmarkInterfaceFunctionWithTypeAssert	200000000	         8.93 ns/op
ok  	local/temp/bench	17.034s
*/