Benchmark of three ways to do optional fields in Go structs

client.go

package client

func IntPtr(n int) *int { return &n }

type FooArgsPtr struct {
	UserID  *int
	User    string
	GroupID *int
	Group   string
}

type FooArgsBool struct {
	ChangeUser  bool
	UserID      int
	User        string
	ChangeGroup bool
	GroupID     int
	Group       string
}

func Int(n int) OptionalInt { return OptionalInt{IsSet: true, Value: n} }

type OptionalInt struct {
	IsSet bool
	Value int
}

type FooArgsOptional struct {
	UserID  OptionalInt
	User    string
	GroupID OptionalInt
	Group   string
}

main_test.go

/* On my machine, I get the following results. I was surprised that pointers are faster here!

cpu: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
BenchmarkPtr-8        	332021145	         3.408 ns/op
BenchmarkBool-8       	327414150	         3.652 ns/op
BenchmarkOptional-8   	326028478	         3.662 ns/op

*/

package main_test

import (
	"testing"

	"optionaltest/client"
)

var (
	sumPtr      int
	sumBool     int
	sumOptional int
)

//go:noinline
func FooPtr(args *client.FooArgsPtr) {
	if args.UserID != nil {
		sumPtr += *args.UserID
	}
	if args.GroupID != nil {
		sumPtr += *args.GroupID
	}
}

//go:noinline
func FooBool(args *client.FooArgsBool) {
	if args.ChangeUser {
		sumBool += args.UserID
	}
	if args.ChangeGroup {
		sumBool += args.GroupID
	}
}

//go:noinline
func FooOptional(args *client.FooArgsOptional) {
	if args.UserID.IsSet {
		sumOptional += args.UserID.Value
	}
	if args.GroupID.IsSet {
		sumOptional += args.GroupID.Value
	}
}

func BenchmarkPtr(b *testing.B) {
	sumPtr = 0
	for i := 0; i < b.N; i++ {
		uid := 100
		args := &client.FooArgsPtr{
			UserID:  &uid,
			GroupID: client.IntPtr(200),
		}
		FooPtr(args)
	}
}

func BenchmarkBool(b *testing.B) {
	sumBool = 0
	for i := 0; i < b.N; i++ {
		uid := 100
		args := &client.FooArgsBool{
			ChangeUser:  true,
			UserID:      uid,
			ChangeGroup: true,
			GroupID:     200,
		}
		FooBool(args)
	}
}

func BenchmarkOptional(b *testing.B) {
	sumOptional = 0
	for i := 0; i < b.N; i++ {
		uid := 100
		args := &client.FooArgsOptional{
			UserID:  client.Int(uid),
			GroupID: client.Int(200),
		}
		FooOptional(args)
	}
}