Lambda vs private function benchmark

test.exs

defmodule Test1 do
  def foo(a) do
    bar = fn x ->
      x + 1
    end

    bar.(a)
  end
end

defmodule Test2 do
  def foo(a) do
    bar(a)
  end

  defp bar(x) do
    x + 1
  end
end

defmodule Benchmark do
  def measure(function) do
    function
    |> :timer.tc()
    |> elem(0)
    |> Kernel./(1_000_000)
  end
end

Benchmark.measure(fn ->
  for i <- 1..10_000_000, do: Test1.foo(i)
end) |> IO.inspect(label: "Lambda")

Benchmark.measure(fn ->
  for i <- 1..10_000_000, do: Test2.foo(i)
end) |> IO.inspect(label: "Private function")

# Lambda: 2.099491
# Private function: 0.698419