BenchDefer.go

package main

import (
	"fmt"
	"time"
)

const (
	numberOperations = 100000000
)

func withoutDefer(i int) (a int) {
	if i&1 == 0 {
		a = i
	} else {
		a = i << 1
	}
	return
}

func withDefer(i int) (a int) {
	defer func() {
		if i&1 == 0 {
			a = i
		} else {
			a = i << 1
		}
	}()
	return
}

func conditionalDefer(i int) (a int) {
	if i&1 == 0 {
		defer func() {
			a = i
		}()
	} else {
		defer func() {
			a = i << 1
		}()
	}
	return
}

func doubleDefer(i int) (a int) {
	defer func() {
		if i&1 == 0 {
			a = i
		} else {
			a = i << 1
		}
	}()

	defer func() {
		a = 3
	}()

	return
}

func tripleDefer(i int) (a int) {
	defer func() {
		if i&1 == 0 {
			a = i
		} else {
			a = i << 1
		}
	}()

	defer func() {
		a = 4
	}()

	defer func() {
		a = 3
	}()

	return
}

func main() {
	fmt.Printf("Bench with %d number of operations\n", numberOperations)
	start := time.Now()
	var total uint64
	for i := 0; i < numberOperations; i++ {
		total += uint64(withoutDefer(i))
	}
	d1 := time.Now().Sub(start).Seconds()
	fmt.Printf("Without defer: %.3f(s) %.3f(op/s)\n", d1, float64(numberOperations)/d1)

	start, total = time.Now(), 0
	for i := 0; i < numberOperations; i++ {
		total += uint64(withDefer(i))
	}
	d2 := time.Now().Sub(start).Seconds()
	fmt.Printf("With defer: %.3f(s) %.3f(op/s)\n", d2, float64(numberOperations)/d2)

	start, total = time.Now(), 0
	for i := 0; i < numberOperations; i++ {
		total += uint64(conditionalDefer(i))
	}
	d3 := time.Now().Sub(start).Seconds()
	fmt.Printf("Conditional defer: %.3f(s) %.3f(op/s)\n", d3, float64(numberOperations)/d3)

	start, total = time.Now(), 0
	for i := 0; i < numberOperations; i++ {
		total += uint64(doubleDefer(i))
	}
	d4 := time.Now().Sub(start).Seconds()
	fmt.Printf("Double defer: %.3f(s) %.3f(op/s)\n", d4, float64(numberOperations)/d4)

	start, total = time.Now(), 0
	for i := 0; i < numberOperations; i++ {
		total += uint64(tripleDefer(i))
	}
	d5 := time.Now().Sub(start).Seconds()
	fmt.Printf("Triple defer: %.3f(s) %.3f(op/s)\n", d5, float64(numberOperations)/d5)

	start, total = time.Now(), 0
	for i := 0; i < numberOperations; i++ {
		total += uint64(doubleDefer(i))
		total += uint64(doubleDefer(i))
	}
	d6 := time.Now().Sub(start).Seconds()
	fmt.Printf("Double(x2) defer: %.3f(s) %.3f(op/s)\n", d6, float64(numberOperations)/d6)
}