Use SO_REUSEPORT

elixir_dummy/lib/elixir_dummy/application.ex

@@ -3,6 +3,11 @@ defmodule Dummy.Application do
 
   use Application
 
+  @sol_socket 1
+  @so_reuseport 15
+
+  @socket_num 36
+
   def start(_type, _args) do
     dispatch =
       :cowboy_router.compile([
@@ -12,21 +17,23 @@ defmodule Dummy.Application do
          ]}
       ])
 
-    children = [
+    children = 0..@socket_num-1
+    |> Enum.map(fn i ->
+      id = :"dummy#{i}"
       %{
-        id: :dummy,
+        id: id,
         start:
           {:cowboy, :start_clear,
            [
-             :dummy,
-             %{max_connections: 999_999, socket_opts: [port: 5000]},
+             id,
+             %{max_connections: 1_000_000, socket_opts: [{:port, 5000}, {:raw, @sol_socket, @so_reuseport, <<1::size(32)>>}]},
              %{max_keepalive: 1_000, env: %{dispatch: dispatch}}
            ]},
         restart: :permanent,
         shutdown: :infinity,
         type: :supervisor
       }
-    ]
+    end)
 
     opts = [strategy: :one_for_one, name: Dummy.Supervisor]
     Supervisor.start_link(children, opts)