Microbenchmark for the cost of posting tasks to different pump types

base/message_loop/message_loop.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 
 #include <queue>
 #include <string>
 
@@ skipping 373 matching lines @@
   // Can only be called from the thread that owns the MessageLoop.
   bool is_running() const;
 
   // Returns true if the message loop has high resolution timers enabled.
   // Provided for testing.
   bool HasHighResolutionTasks();
 
   // Returns true if the message loop is "idle". Provided for testing.
   bool IsIdleForTesting();
 
+  // Wakes up the message pump. Can be called on any thread. The caller is
+  // responsible for synchronizing ScheduleWork() calls.
+  void ScheduleWork(bool was_empty);
+
+  // Returns the TaskAnnotator which is used to add debug information to posted
+  // tasks.
+  debug::TaskAnnotator* task_annotator() { return &task_annotator_; }
+
+  // Runs the specified PendingTask.
+  void RunTask(const PendingTask& pending_task);
+
   //----------------------------------------------------------------------------
  protected:
   scoped_ptr<MessagePump> pump_;
 
  private:
-  friend class internal::IncomingTaskQueue;
   friend class RunLoop;
 
   // Configures various members for the two constructors.
   void Init();
 
   // Invokes the actual run loop using the message pump.
   void RunHandler();
 
   // Called to process any delayed non-nestable tasks.
   bool ProcessNextDelayedNonNestableTask();
 
-  // Runs the specified PendingTask.
-  void RunTask(const PendingTask& pending_task);
-
   // Calls RunTask or queues the pending_task on the deferred task list if it
   // cannot be run right now.  Returns true if the task was run.
   bool DeferOrRunPendingTask(const PendingTask& pending_task);
 
   // Adds the pending task to delayed_work_queue_.
   void AddToDelayedWorkQueue(const PendingTask& pending_task);
 
   // Delete tasks that haven't run yet without running them.  Used in the
   // destructor to make sure all the task's destructors get called.  Returns
   // true if some work was done.
   bool DeletePendingTasks();
 
-  // Returns the TaskAnnotator which is used to add debug information to posted
-  // tasks.
-  debug::TaskAnnotator* task_annotator() { return &task_annotator_; }
-
   // Loads tasks from the incoming queue to |work_queue_| if the latter is
   // empty.
   void ReloadWorkQueue();
 
-  // Wakes up the message pump. Can be called on any thread. The caller is
-  // responsible for synchronizing ScheduleWork() calls.
-  void ScheduleWork(bool was_empty);
-
   // Start recording histogram info about events and action IF it was enabled
   // and IF the statistics recorder can accept a registration of our histogram.
   void StartHistogrammer();
 
   // Add occurrence of event to our histogram, so that we can see what is being
   // done in a specific MessageLoop instance (i.e., specific thread).
   // If message_histogram_ is NULL, this is a no-op.
   void HistogramEvent(int event);
 
   // MessagePump::Delegate methods:
@@ skipping 202 matching lines @@
 
 // Do not add any member variables to MessageLoopForIO!  This is important b/c
 // MessageLoopForIO is often allocated via MessageLoop(TYPE_IO).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 COMPILE_ASSERT(sizeof(MessageLoop) == sizeof(MessageLoopForIO),
                MessageLoopForIO_should_not_have_extra_member_variables);
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_