3 files changed, 20 insertions, 4 deletions
diff --git a/actioncable/lib/action_cable/subscription_adapter/async.rb b/actioncable/lib/action_cable/subscription_adapter/async.rb
index 85d4892e4c..c88b03947a 100644
--- a/actioncable/lib/action_cable/subscription_adapter/async.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/async.rb
@@ -10,11 +10,11 @@ module ActionCable
 
         class AsyncSubscriberMap < SubscriberMap
           def add_subscriber(*)
-            ::EM.next_tick { super }
+            Concurrent.global_io_executor.post { super }
           end
 
           def invoke_callback(*)
-            ::EM.next_tick { super }
+            Concurrent.global_io_executor.post { super }
           end
         end
     end
diff --git a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
index 78f8aeb599..3ce1bbed68 100644
--- a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
@@ -63,7 +63,7 @@ module ActionCable
                     case action
                     when :listen
                       pg_conn.exec("LISTEN #{pg_conn.escape_identifier channel}")
-                      ::EM.next_tick(&callback) if callback
+                      Concurrent.global_io_executor << callback if callback
                     when :unlisten
                       pg_conn.exec("UNLISTEN #{pg_conn.escape_identifier channel}")
                     when :shutdown
@@ -93,7 +93,7 @@ module ActionCable
           end
 
           def invoke_callback(*)
-            ::EM.next_tick { super }
+            Concurrent.global_io_executor.post { super }
           end
         end
     end
diff --git a/actioncable/lib/action_cable/subscription_adapter/redis.rb b/actioncable/lib/action_cable/subscription_adapter/redis.rb
index 3b86354621..a035e3988d 100644
--- a/actioncable/lib/action_cable/subscription_adapter/redis.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/redis.rb
@@ -1,11 +1,18 @@
+require 'thread'
+
 gem 'em-hiredis', '~> 0.3.0'
 gem 'redis', '~> 3.0'
 require 'em-hiredis'
 require 'redis'
 
+EventMachine.epoll  if EventMachine.epoll?
+EventMachine.kqueue if EventMachine.kqueue?
+
 module ActionCable
   module SubscriptionAdapter
     class Redis < Base # :nodoc:
+      @@mutex = Mutex.new
+
       def broadcast(channel, payload)
         redis_connection_for_broadcasts.publish(channel, payload)
       end
@@ -27,6 +34,7 @@ module ActionCable
 
       private
         def redis_connection_for_subscriptions
+          ensure_reactor_running
           @redis_connection_for_subscriptions ||= EM::Hiredis.connect(@server.config.cable[:url]).tap do |redis|
             redis.on(:reconnect_failed) do
               @logger.info "[ActionCable] Redis reconnect failed."
@@ -37,6 +45,14 @@ module ActionCable
         def redis_connection_for_broadcasts
           @redis_connection_for_broadcasts ||= ::Redis.new(@server.config.cable)
         end
+
+        def ensure_reactor_running
+          return if EventMachine.reactor_running?
+          @@mutex.synchronize do
+            Thread.new { EventMachine.run } unless EventMachine.reactor_running?
+            Thread.pass until EventMachine.reactor_running?
+          end
+        end
     end
   end
 end