benchmark_test.go

package ghost

import (
	"reflect"
	"testing"
)

type BarFunc func() int

type Foo struct{}

// Bar is a method function which is in form of BarFunc.
func (f *Foo) Bar() int {
	return 0
}

func (f *Foo) Bind(v interface{}) BarFunc {
	if fn, ok := v.(func(*Foo) int); ok {
		return func() int {
			return fn(f)
		}
	}
	return nil
}

var (
	f = &Foo{}
	mt, _ = reflect.TypeOf(f).MethodByName("Bar")
	mv = reflect.ValueOf(f).MethodByName("Bar")
)

func Benchmark_CallBar1(b *testing.B) {
	fn, _ := mv.Interface().(func() int)
	for i := 0; i < b.N; i++ {
		fn()
	}
}

func Benchmark_CallBar2(b *testing.B) {
	// This way is 50x faster than Benchmark_CallBar1
	fn := f.Bind(mt.Func.Interface())
	for i := 0; i < b.N; i++ {
		fn()
	}
}