Trying a custom executor

lib/shoryuken/launcher.rb

@@ -36,12 +36,12 @@ def stop
     private
 
     def executor
-      Concurrent.global_io_executor
+      @executor ||= Concurrent::FixedThreadPool.new(pool_size, max_queue: pool_size)
     end
 
     def start_managers
       @managers.each do |manager|
-        Concurrent::Promise.execute { manager.start }.rescue do |ex|
+        Concurrent::Promise.execute(executor: executor) { manager.start }.rescue do |ex|
           log_manager_failure(ex)
           start_soft_shutdown
         end
@@ -85,12 +85,17 @@ def stop_callback
       fire_event(:shutdown, true)
     end
 
+    def pool_size
+      Shoryuken.groups.sum { |(_group, options)| options[:concurrency] }
+    end
+
     def create_managers
       Shoryuken.groups.map do |group, options|
         Shoryuken::Manager.new(
           Shoryuken::Fetcher.new(group),
           Shoryuken.polling_strategy(group).new(options[:queues]),
-          options[:concurrency]
+          options[:concurrency],
+          executor: executor
         )
       end
     end

lib/shoryuken/manager.rb

@@ -4,14 +4,15 @@ class Manager
 
     BATCH_LIMIT = 10
     # See https://github.com/phstc/shoryuken/issues/348#issuecomment-292847028
-    MIN_DISPATCH_INTERVAL = 0.5
+    MIN_DISPATCH_INTERVAL = 0.1
 
-    def initialize(fetcher, polling_strategy, concurrency)
+    def initialize(fetcher, polling_strategy, concurrency, executor)
       @fetcher          = fetcher
       @polling_strategy = polling_strategy
       @max_processors   = concurrency
       @busy_processors  = Concurrent::AtomicFixnum.new(0)
       @done             = Concurrent::AtomicBoolean.new(false)
+      @executor         = executor
     end
 
     def start
@@ -68,7 +69,7 @@ def assign(queue_name, sqs_msg)
 
       @busy_processors.increment
 
-      Concurrent::Promise.execute {
+      Concurrent::Promise.execute(executor: @executor) {
         Processor.new(queue_name, sqs_msg).process
       }.then { processor_done }.rescue { processor_done }
     end