diff --git a/lib/sidetiq.rb b/lib/sidetiq.rb
index 82a2df6..d50599b 100644
--- a/lib/sidetiq.rb
+++ b/lib/sidetiq.rb
@@ -24,6 +24,7 @@ require 'sidetiq/version'
 require 'sidetiq/middleware/history'
 
 # actor topology
+require 'sidetiq/actor'
 require 'sidetiq/actor/clock'
 require 'sidetiq/actor/handler'
 require 'sidetiq/supervisor'
diff --git a/lib/sidetiq/actor.rb b/lib/sidetiq/actor.rb
new file mode 100644
index 0000000..7020e2d
--- /dev/null
+++ b/lib/sidetiq/actor.rb
@@ -0,0 +1,18 @@
+module Sidetiq
+  module Actor
+    def self.included(base)
+      base.__send__(:include, Celluloid)
+    end
+
+    def initialize(*args, &block)
+      log_call "initialize"
+      super
+    end
+
+    private
+
+    def log_call(call)
+      info "#{self.class.name} id: #{object_id} #{call}"
+    end
+  end
+end
diff --git a/lib/sidetiq/actor/clock.rb b/lib/sidetiq/actor/clock.rb
index 3cb6e1c..abc11e2 100644
--- a/lib/sidetiq/actor/clock.rb
+++ b/lib/sidetiq/actor/clock.rb
@@ -1,12 +1,12 @@
 module Sidetiq
   module Actor
     class Clock < Sidetiq::Clock
-      include Celluloid
+      include Sidetiq::Actor
       include Sidekiq::ExceptionHandler
 
       # Public: Starts the clock loop.
       def start!
-        info "Sidetiq::Clock start"
+        debug "Sidetiq::Clock looping ..."
         loop!
       end
 
diff --git a/lib/sidetiq/actor/handler.rb b/lib/sidetiq/actor/handler.rb
index f1dfda2..0f8b126 100644
--- a/lib/sidetiq/actor/handler.rb
+++ b/lib/sidetiq/actor/handler.rb
@@ -1,12 +1,7 @@
 module Sidetiq
   module Actor
     class Handler < Sidetiq::Handler
-      include Celluloid
-
-      def initialize
-        info "Sidetiq::Handler initialize #{object_id}"
-        super
-      end
+      include Sidetiq::Actor
     end
   end
 end
diff --git a/lib/sidetiq/config.rb b/lib/sidetiq/config.rb
index 4b95848..4a295c7 100644
--- a/lib/sidetiq/config.rb
+++ b/lib/sidetiq/config.rb
@@ -28,7 +28,7 @@ module Sidetiq
     config.resolution = 1
     config.lock_expire = 1000
     config.utc = false
-    config.handler_pool_size = 5
+    config.handler_pool_size = nil
   end
 end
 
diff --git a/lib/sidetiq/handler.rb b/lib/sidetiq/handler.rb
index add2899..875db36 100644
--- a/lib/sidetiq/handler.rb
+++ b/lib/sidetiq/handler.rb
@@ -18,6 +18,7 @@ module Sidetiq
       end
     rescue StandardError => e
       handle_exception(e, context: "Sidetiq::Handler#dispatch")
+      raise e
     end
 
     private
@@ -43,6 +44,7 @@ module Sidetiq
       end
     rescue StandardError => e
       handle_exception(e, context: "Sidetiq::Handler#enqueue")
+      raise e
     end
   end
 end
diff --git a/lib/sidetiq/supervisor.rb b/lib/sidetiq/supervisor.rb
index c8da306..27d3785 100644
--- a/lib/sidetiq/supervisor.rb
+++ b/lib/sidetiq/supervisor.rb
@@ -3,9 +3,15 @@ module Sidetiq
     supervise Sidetiq::Actor::Clock, as: :sidetiq_clock
 
     if Sidekiq.server?
-      pool Sidetiq::Actor::Handler,
-           as: :sidetiq_handler,
-           size: Sidetiq.config.handler_pool_size
+      if handler_pool_size = Sidetiq.config.handler_pool_size
+        pool Sidetiq::Actor::Handler,
+             as: :sidetiq_handler,
+             size: handler_pool_size
+      else
+        # Use Celluloid's CPU-based default.
+        pool Sidetiq::Actor::Handler,
+             as: :sidetiq_handler
+      end
     end
 
     class << self
@@ -24,15 +30,11 @@ module Sidetiq
       def run!
         motd
         info "Sidetiq::Supervisor start"
-
         super
       end
 
       def run
-        motd
-        info "Sidetiq::Supervisor start (foreground)"
-
-        super
+        raise "Sidetiq::Supervisor should not be run in foreground."
       end
 
       private