Add noop benchmarking for overhead

Author: José Valim

bench/erlang.exs

@@ -3,17 +3,6 @@
 
 Code.require_file "shared.exs", __DIR__
 
-defmodule ErlangRegistry do
-  def whereis_name(name) do
-    :erlang.whereis(name)
-  end
-
-  def register_name(name, pid) when pid == self() do
-    :erlang.register(name, pid)
-    :yes
-  end
-end
-
 tasks = String.to_integer System.get_env("TASKS") || "1"
 IO.puts "erlang: registering #{tasks} x 10000 entries"
 
@@ -28,4 +17,4 @@ names =
   |> Enum.each(&Task.await(&1, :infinity))
 end) |> IO.inspect
 
-Shared.check(names)
+Shared.check(names)

bench/noop.exs

@@ -0,0 +1,25 @@
+# MIX_ENV=bench mix run bench/noop.exs
+# TASKS=8 MIX_ENV=bench mix run bench/noop.exs
+
+Code.require_file "shared.exs", __DIR__
+
+defmodule NoopRegistry do
+  def whereis_name(_name), do: :undefined
+  def register_name(_name, pid) when pid == self(), do: :yes
+end
+
+tasks = String.to_integer System.get_env("TASKS") || "1"
+IO.puts "noop: registering #{tasks} x 10000 entries"
+
+names =
+  for _ <- 1..tasks do
+    for i <- 1..10000, do: {:via, NoopRegistry, i}
+  end
+
+:timer.tc(fn ->
+  names
+  |> Enum.map(&Task.async(Shared, :register, [&1]))
+  |> Enum.each(&Task.await(&1, :infinity))
+end) |> IO.inspect
+
+Shared.check(names)

bench/registry.exs

@@ -20,4 +20,4 @@ names =
   |> Enum.each(&Task.await(&1, :infinity))
 end) |> IO.inspect
 
-Shared.check(names)
+Shared.check(names)