KinoBenchee

Mix.install([
  {:kino_benchee, "~> 0.1"}
])

Benchmark

defmodule Digits do
  def count_by_integer_digits(n) do
    n |> Integer.digits() |> length()
  end

  def count_by_common_logarithm(n) do
    n |> :math.log10() |> floor() |> Kernel.+(1)
  end
end

Digits.count_by_integer_digits(123)

Digits.count_by_common_logarithm(123)

defmodule MyBenchmark do
  def run() do
    Benchee.run(
      %{
        "Integer.digits" => fn -> Digits.count_by_integer_digits(123456789) end,
        ":math.log10" => fn -> Digits.count_by_common_logarithm(123456789) end
      },
      memory_time: 2,
      reduction_time: 2
    )
  end
end

MyBenchmark.run()