Benchmark for io data vs strings

bench.md

Simple Interpolation

Operating System: macOS
CPU Information: Intel(R) Core(TM) i5-7267U CPU @ 3.10GHz
Number of Available Cores: 4
Available memory: 8 GB
Elixir 1.8.1
Erlang 21.0.2

Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
parallel: 1
inputs: none specified
Estimated total run time: 14 s

Benchmarking iodata...
Benchmarking string...

Name             ips        average  deviation         median         99th %
iodata        6.20 M      161.33 ns  ±4226.50%           0 ns        1000 ns
string        3.68 M      271.40 ns ±11207.73%           0 ns        1000 ns

Comparison:
iodata        6.20 M
string        3.68 M - 1.68x slower +110.08 ns

Complex interpolation

Benchmarking iodata...
Benchmarking string...

Name             ips        average  deviation         median         99th %
iodata        1.75 M        0.57 μs  ±7439.11%           0 μs        0.99 μs
string        0.65 M        1.53 μs   ±875.52%        0.99 μs        1.99 μs

Comparison:
iodata        1.75 M
string        0.65 M - 2.68x slower +0.96 μs

code.ex

defmodule View do
  use Spigot, :view

  def render("iodata", %{name: name}) do
    ~i(Hello, #{name})
  end

  def render("string", %{name: name}) do
    ~s(Hello, #{name})
  end
  
  def render("iodata-long", %{character: character}) do
    ~E"""
    <%= character.name %>
    -----

    HP: <%= character.hp %>/<%= character.maxhp %>
    SP: <%= character.sp %>/<%= character.maxsp %>
    EP: <%= character.ep %>/<%= character.maxep %>

    Items:
    -------

    <%= Enum.map(character.items, &render("item-io", &1)) %>
    """
  end

  def render("item-io", %{name: name}) do
    ~i(- #{name})
  end

  def render("string-long", %{character: character}) do
    """
    #{character.name}
    -----

    HP: #{character.hp}/#{character.maxhp}
    SP: #{character.sp}/#{character.maxsp}
    EP: #{character.ep}/#{character.maxep}

    Items:
    -------

    #{Enum.map(character.items, &render("item-string", &1))}
    """
  end

  def render("item-string", %{name: name}) do
    ~s(- #{name})
  end
end

character = %{
  name: "Eric",
  hp: 50,
  maxhp: 50,
  sp: 35,
  maxsp: 35,
  ep: 22,
  maxep: 25,
  items: [
    %{name: "Potion"},
    %{name: "Sword"}
  ]
}

Benchee.run(%{
  "iodata" => fn -> View.render("iodata", %{name: "Eric"}) end,
  "string" => fn -> View.render("string", %{name: "Eric"}) end
})

Benchee.run(%{
  "iodata" => fn -> View.render("iodata-long", %{character: character}) end,
  "string" => fn -> View.render("string-long", %{character: character}) end,
})