A small elixir script for bench marking the startup times of applications, specify the top-level app and this will print the slowest application in the tree

bench_startup.exs

excluded = [:stdlib, :kernel, :compiler]

bench_startup = fn bench_startup, acc, app ->
  if acc[app] do 
    acc
  else
    apps = Application.spec(app, :applications) -- excluded
    inc_apps = Application.spec(app, :included_applications) -- excluded

    all_apps = apps ++ inc_apps

    acc = 
      Enum.reduce(all_apps, acc, fn app_name, acc ->
        bench_startup.(bench_startup, acc, app_name)
      end)

    {elapsed, _value} = :timer.tc(fn -> 
      Application.ensure_all_started(app)
    end)

    Map.put(acc, app, elapsed)
  end
end

times_by_app = bench_startup.(bench_startup, %{}, :your_app_name)
  
apps_by_startup =
  Enum.sort_by(times_by_app, fn {_app, time} ->
    time
  end)

Enum.each(Enum.reverse(apps_by_startup), fn {app, time} ->
  IO.puts "#{app}: #{time/1000}ms"
end)