Collect profiler stats from browser child processes.

chrome/browser/metrics/tracking_synchronizer.h

 // Copyright (c) 2011 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 CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_
 #define CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/message_loop.h"
+#include "base/process.h"
 #include "base/time.h"
 #include "base/values.h"
 #include "chrome/browser/ui/webui/profiler_ui.h"
-#include "content/common/child_process_info.h"
+#include "content/browser/profiler_controller.h"
 #include "content/public/browser/browser_thread.h"
 
-// This class maintains state that is used to upload tracking data from the
+// This class maintains state that is used to upload profiler data from the
 // various processes, into the browser process. Such transactions are usually
 // instigated by the browser. In general, a process will respond by gathering
-// tracking data, and transmitting the pickled tracking data. We collect the
+// profiler data, and transmitting the pickled profiler data. We collect the
 // data in asynchronous mode that doesn't block the UI thread.
 //
 // To assure that all the processes have responded, a counter is maintained
 // to indicate the number of pending (not yet responsive) processes. We tag
 // each group of requests with a sequence number. For each group of requests, we
 // create RequestContext object which stores the sequence number, pending
 // processes and the callback_object that needs to be notified when we receive
 // an update from processes. When an update arrives we find the RequestContext
-// associated with sequence number and send the unpickled tracking data to the
+// associated with sequence number and send the unpickled profiler data to the
 // |callback_object_|.
 
 namespace chrome_browser_metrics {
 
-class TrackingSynchronizer : public
-    base::RefCountedThreadSafe<TrackingSynchronizer> {
+class TrackingSynchronizer
+    : public ProfilerSubscriber,
+      public base::RefCountedThreadSafe<TrackingSynchronizer> {
  public:
   // The "RequestContext" structure describes an individual request received
   // from the UI.
   struct RequestContext {
     RequestContext(const base::WeakPtr<ProfilerUI>& callback_object,
                    int sequence_number,
-                   int processes_pending,
+                   int ui_processes_pending,
+                   int io_processes_pending,
+                   int threads_pending,
                    base::TimeTicks callback_start_time)
         : callback_object_(callback_object),
           sequence_number_(sequence_number),
-          processes_pending_(processes_pending),
+          ui_processes_pending_(ui_processes_pending),
+          io_processes_pending_(io_processes_pending),
+          threads_pending_(threads_pending),
           request_start_time_(callback_start_time) {
     }
 
     ~RequestContext() {}
 
     // Requests are made to asynchronously send data to the |callback_object_|.
     base::WeakPtr<ProfilerUI> callback_object_;
 
     // The sequence number used by the most recent update request to contact all
     // processes.
     int sequence_number_;
 
-    // The number of processes that have not yet responded to requests.
-    int processes_pending_;
+    // The number of renderer processes that have not yet responded to requests.
+    // This is updated on UI thread.
+    int ui_processes_pending_;
+
+    // The number of browser child processes that have not yet responded to
+    // requests. This is updated on IO thread.
+    int io_processes_pending_;
+
+    // The number of threads (UI and IO) we are waiting for. This is initialized
+    // to 2. This is decremented by 1 whenever either ui_processes_pending_ or
+    // io_processes_pending_ become zero (in other words, this will be zero when
+    // ui_processes_pending_ and io_processes_pending_ are zero).
+    // This is updated on UI thread.
+    int threads_pending_;
 
     // The time when we were told to start the fetching of data from processes.
     base::TimeTicks request_start_time_;
   };
 
   // A map from sequence_number_ to the actual RequestContexts.
   typedef std::map<int, RequestContext*> RequestContextMap;
 
+  // The DecrementProcessesCallback receives one argument:
+  // RequestContext request - the request in which we need to decrement the
+  // pending processes count (either ui_processes_pending_ or
+  // io_processes_pending_).
+  typedef base::Callback<void(RequestContext*)> DecrementProcessesCallback;
+
   // Construction also sets up the global singleton instance. This instance is
   // used to communicate between the IO and UI thread, and is destroyed only as
   // the main thread (browser_main) terminates, which means the IO thread has
   // already completed, and will not need this instance any further.
   TrackingSynchronizer();
 
-  // Return pointer to the singleton instance, which is allocated and
-  // deallocated on the main UI thread (during system startup and teardown).
-  static TrackingSynchronizer* CurrentSynchronizer();
-
   // Contact all processes, and get them to upload to the browser any/all
-  // changes to tracking data. It calls |callback_object|'s SetData method with
+  // changes to profiler data. It calls |callback_object|'s SetData method with
   // the data received from each sub-process.
   // This method is accessible on UI thread.
-  static void FetchTrackingDataAsynchronously(
+  static void FetchProfilerDataAsynchronously(
       const base::WeakPtr<ProfilerUI>& callback_object);
 
-  // Contact all processes and set tracking status to |enable|.
+  // Contact all processes and set profiler status to |enable|.
   // This method is accessible on UI thread.
-  static void SetTrackingStatus(bool enable);
+  static void SetProfilerStatus(bool enable);
 
-  // Respond to this message from the renderer by setting the tracking status
-  // (SetTrackingStatusInProcess) in that renderer process.
-  // |process_id| is used to find the renderer process.
+  // Respond to this message from the renderer by setting the profiler status
+  // (SendRendererSetProfilerStatusOnUI) in that renderer process.
+  // |renderer_process_id| is used to find the renderer process.
   // This method is accessible on IO thread.
-  static void IsTrackingEnabled(int process_id);
+  static void IsProfilerEnabledForRenderer(int renderer_process_id);
 
-  // Get the current tracking status from the browser process and set it in the
-  // renderer process. |process_id| is used to find the renderer process.
-  // This method is accessible on UI thread.
-  static void SetTrackingStatusInProcess(int process_id);
+  // Deserialize the profiler data and record that we have received profiler
+  // data from a renderer process. This method posts a task to call
+  // OnRendererProfilerDatatCollectedOnUI on UI thread to send the
+  // |profiler_data| to callback_object_.
+  // This method is accessible on IO thread.
+  static void OnRendererProfilerDatatCollected(
+      int sequence_number,
+      const std::string& profiler_data);
 
-  // Deserialize the tracking data and record that we have received tracking
-  // data from a process. This method posts a task to call
-  // DeserializeTrackingListOnUI on UI thread to send the |tracking_data| to
-  // callback_object_. This method is accessible on IO thread.
-  static void DeserializeTrackingList(
+  // ------------------------------------------------------
+  // ProfilerSubscriber methods for browser child processes
+  // ------------------------------------------------------
+
+  // Deserialize the profiler data and record that we have received profiler
+  // data from a browser child process. This method is accessible on IO thread.
+  virtual void OnBrowserChildProfilerDataCollected(
       int sequence_number,
-      const std::string& tracking_data,
-      ChildProcessInfo::ProcessType process_type);
+      const std::string& profiler_data) OVERRIDE;
 
-  // Deserialize the tracking data and record that we have received tracking
-  // data from a process. This method is accessible on UI thread.
-  static void DeserializeTrackingListOnUI(
-      int sequence_number,
-      const std::string& tracking_data,
-      ChildProcessInfo::ProcessType process_type);
+  // Respond to this message from the browser child process by setting the
+  // profiler status in that browser child process. |child_process_id| is used
+  // to find the child process. This method is accessible on IO thread.
+  virtual void OnIsProfilerEnabledForChildProcess(
+      base::ProcessId child_process_id) OVERRIDE;
 
  private:
   friend class base::RefCountedThreadSafe<TrackingSynchronizer>;
 
   virtual ~TrackingSynchronizer();
 
+  // Return pointer to the singleton instance, which is allocated and
+  // deallocated on the main UI thread (during system startup and teardown).
+  static TrackingSynchronizer* CurrentSynchronizer();
+
   // Establish a new sequence_number_, and use it to notify all the processes of
-  // the need to supply, to the browser, their tracking data. It also registers
+  // the need to supply, to the browser, their profiler data. It also registers
   // |callback_object| in |outstanding_requests_| map. Return the
   // sequence_number_ that was used. This method is accessible on UI thread.
   int RegisterAndNotifyAllProcesses(
       const base::WeakPtr<ProfilerUI>& callback_object);
 
-  // It finds the |callback_object_| in |outstanding_requests_| map for the
-  // given |sequence_number| and notifies the |callback_object_| about the
-  // |value|. This is called whenever we receive tracked data from processes. It
-  // also records that we are waiting for one less tracking data from a process
-  // for the given sequence number. If we have received a response from all
-  // renderers, then it deletes the entry for sequence_number from
-  // |outstanding_requests_| map. This method is accessible on UI thread.
-  void DecrementPendingProcessesAndSendData(int sequence_number,
-                                            base::DictionaryValue* value);
+  // Notify all renderer processes that they need to supply, to the browser,
+  // their profiler data. This method is accessible on UI thread.
+  void NotifyAllRendererProcesses(RequestContext* request);
 
-  // Records that we are waiting for one less tracking data from a process for
-  // the given sequence number.
+  // Notify all browser child processes that they need to supply, to the
+  // browser, their profiler data. This method is accessible on IO thread.
+  void NotifyAllChildProcesses(RequestContext* request);
+
+  // Deserialize the profiler data and record that we have received profiler
+  // data from a renderer process. This method is accessible on UI thread.
+  static void OnRendererProfilerDatatCollectedOnUI(
+      int sequence_number,
+      const std::string& profiler_data);
+
+  // It builds a DecrementProcessesCallback for DecrementUIProcesses to record
+  // that we are waiting for one less profiler data from a process for the given
+  // sequence number and it calls DecrementPendingProcessesAndSendData to send
+  // the data to requester. This method is accessible on UI thread.
+  void DecrementPendingProcessesAndSendDataOnUI(int sequence_number,
+                                                base::DictionaryValue* value);
+
+  // It builds a DecrementProcessesCallback for DecrementIOProcesses to record
+  // that we are waiting for one less profiler data from a process for the given
+  // sequence number and it calls DecrementPendingProcessesAndSendData to send
+  // the data to requester. This method is accessible on IO thread.
+  void DecrementPendingProcessesAndSendDataOnIO(int sequence_number,
+                                                base::DictionaryValue* value);
+
+  // It finds the Request in |outstanding_requests_| map for the given
+  // |sequence_number| and notifies the Request's |callback_object_| about the
+  // |value|. It posts a task (RunDecrementProcessesCallback) on
+  // |callback_thread| to call |decrement_pending_process_cb| (which records
+  // that we are waiting for one less profiler data from a process for the
+  // given sequence number). This method is accessible on UI thread.
+  void DecrementPendingProcessesAndSendData(
+      int sequence_number,
+      base::DictionaryValue* value,
+      MessageLoop* callback_thread,
+      const DecrementProcessesCallback& decrement_pending_process_cb);
+
+  // Records that we are waiting for one less profiler data from a process for
+  // the given sequence number. If we have received a response from all
+  // renderers, then it calls DeleteIfAllDone which will delete the entry for
+  // sequence_number from |outstanding_requests_| map if |request|'s
+  // |threads_pending_| is zero.
+  // This method is accessible on UI thread (for renderer process).
+  void DecrementUIProcesses(RequestContext* request);
+
+  // Records that we are waiting for one less profiler data from a process for
+  // the given sequence number. If we have received a response from all child
+  // processes, then it posts a task on UI thread to call DeleteIfAllDone which
+  // will delete the entry for sequence_number from |outstanding_requests_| map
+  // if |request|'s |threads_pending_| is zero.
+  // This method is accessible on IO thread (for browser child process).
+  void DecrementIOProcesses(RequestContext* request);
+
+  // Deletes the entry for sequence_number from |outstanding_requests_| map (by
+  // calling ForceProfilerSynchronizationDoneCallback) if we have heard from all
+  // child and renderer processes.
   // This method is accessible on UI thread.
-  void DecrementPendingProcesses(int sequence_number);
+  void DeleteIfAllDone(RequestContext* request);
 
   // When all changes have been acquired, or when the wait time expires
   // (whichever is sooner), this method is called. This method deletes the entry
   // for the given sequence_number from |outstanding_requests_| map.
   // This method is accessible on UI thread.
-  void ForceTrackingSynchronizationDoneCallback(int sequence_number);
+  void ForceProfilerSynchronizationDoneCallback(int sequence_number);
 
   // Get a new sequence number to be sent to processes from browser process.
   // This method is accessible on UI thread.
   int GetNextAvailableSequenceNumber();
 
+  // Runs the |decrement_pending_process_cb| callback.
+  // |decrement_pending_process_cb| is either |DecrementUIProcesses| or
+  // |DecrementIOProcesses| which decrements |request|'s pending process count.
+  void RunDecrementProcessesCallback(
+      const DecrementProcessesCallback& decrement_pending_process_cb,
+      RequestContext* request);
+
+  // Contact all browser child processes and set profiler status to |enable|.
+  // This method is accessible on IO thread.
+  static void SetProfilerStatusInChildProcesses(bool enable);
+
+  // Get the current profiler status from the browser process and set it in the
+  // renderer process. |renderer_process_id| is used to find the renderer
+  // process. This method is accessible on UI thread.
+  static void SendRendererSetProfilerStatusOnUI(int renderer_process_id);
+
+  // Get the current profiler status from the browser process and set it in the
+  // browser child process. |child_process_id| is used to find the browser child
+  // process. This method is accessible on IO thread.
+  static void SendChildSetProfilerStatusOnIO(base::ProcessId child_process_id);
+
   // Map of all outstanding RequestContexts, from sequence_number_ to
   // RequestContext.
   RequestContextMap outstanding_requests_;
 
   // We don't track the actual processes that are contacted for an update, only
   // the count of the number of processes, and we can sometimes time-out and
   // give up on a "slow to respond" process.  We use a sequence_number to be
   // sure a response from a process is associated with the current round of
   // requests. All sequence numbers used are non-negative.
   // last_used_sequence_number_ is the most recently used number (used to avoid
   // reuse for a long time).
   int last_used_sequence_number_;
 
   // This singleton instance should be started during the single threaded
   // portion of main(). It initializes globals to provide support for all future
   // calls. This object is created on the UI thread, and it is destroyed after
   // all the other threads have gone away. As a result, it is ok to call it
-  // from the UI thread, or for about:tracking.
+  // from the UI thread, or for about:profiler.
   static TrackingSynchronizer* tracking_synchronizer_;
 
   DISALLOW_COPY_AND_ASSIGN(TrackingSynchronizer);
 };
 
 }  // namespace chrome_browser_metrics
 
 #endif  // CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_