GopherJS's defer performance

bench_test.go

package test

import (
        "testing"
)

var i = 0

func begin() {
        i++
}

func end() {
        i--
}

func fooNormal() {
        begin()
        end()
}

func fooDefer() {
        begin()
        defer end()
}

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

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

result

$ gopherjs version
GopherJS 1.8-1

$ gopherjs test --bench="." github.com/hajimehoshi/test
gopherjs: Source maps disabled. Install source-map-support module for nice stack traces. See https://github.com/gopherjs/gopherjs#gopherjs-run-gopherjs-test.
BenchmarkNormal         300000000                5.26 ns/op
BenchmarkDefer          10000000               137 ns/op
PASS
fatal error: all goroutines are asleep - deadlock!
FAIL    github.com/hajimehoshi/test     4.047s