Collect profiler stats from browser child processes.

chrome/browser/metrics/tracking_synchronizer.cc

Index: chrome/browser/metrics/tracking_synchronizer.cc
===================================================================
--- chrome/browser/metrics/tracking_synchronizer.cc	(revision 112492)
+++ chrome/browser/metrics/tracking_synchronizer.cc	(working copy)
@@ -5,17 +5,13 @@
 #include "chrome/browser/metrics/tracking_synchronizer.h"
 
 #include "base/bind.h"
-#include "base/json/json_reader.h"
-#include "base/json/json_writer.h"
-#include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/process_util.h"
 #include "base/threading/thread.h"
 #include "base/tracked_objects.h"
-#include "chrome/browser/ui/webui/tracing_ui.h"
-#include "chrome/common/chrome_constants.h"
-#include "chrome/common/render_messages.h"
+#include "content/common/child_process_info.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/profiler_controller.h"
 #include "content/public/common/process_type.h"
 
 using base::TimeTicks;
@@ -23,6 +19,142 @@
 
 namespace chrome_browser_metrics {
 
+// The "RequestContext" structure describes an individual request received
+// from the UI. All methods are accessible on UI thread.
+class RequestContext {
+ public:
+  // A map from sequence_number_ to the actual RequestContexts.
+  typedef std::map<int, RequestContext*> RequestContextMap;
+
+  ~RequestContext() {}
+
+  RequestContext(const base::WeakPtr<ProfilerUI>& callback_object,
+                 int sequence_number)
+      : callback_object_(callback_object),
+        sequence_number_(sequence_number),
+        received_process_group_count_(0),
+        processes_pending_(0) {
+  }
+
+  void SetReceivedProcessGroupCount(bool done) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    received_process_group_count_ = done;
+  }
+
+  // Methods for book keeping of processes_pending_.
+  void IncrementProcessesPending() {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    ++processes_pending_;
+  }
+
+  void AddProcessesPending(int processes_pending) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    processes_pending_ += processes_pending;
+  }
+
+  void DecrementProcessesPending() {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+    --processes_pending_;
+  }
+
+  // Records that we are waiting for one less tracking data from a process for
+  // the given sequence number. If |received_process_group_count_| and
+  // |processes_pending_| are zero, then delete the current object by calling
+  // Unregister.
+  void DeleteIfAllDone() {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+    if (processes_pending_ <= 0 && received_process_group_count_) {
+      RequestContext::Unregister(sequence_number_);
+    }
+  }
+
+
+  // Register |callback_object| in |outstanding_requests_| map for the given
+  // |sequence_number|.
+  static RequestContext* Register(
+      int sequence_number,
+      const base::WeakPtr<ProfilerUI>& callback_object) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+    RequestContext* request = new RequestContext(
+        callback_object, sequence_number);
+    outstanding_requests_.Get()[sequence_number] = request;
+
+    return request;
+  }
+
+  // Find the |RequestContext| in |outstanding_requests_| map for the given
+  // |sequence_number|.
+  static RequestContext* GetRequestContext(int sequence_number) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+    RequestContextMap::iterator it =
+        outstanding_requests_.Get().find(sequence_number);
+    if (it == outstanding_requests_.Get().end())
+      return NULL;
+
+    RequestContext* request = NULL;
+    request = it->second;
+    DCHECK(sequence_number == request->sequence_number_);
+    return request;
+  }
+
+  // Delete the entry for the given sequence_number| from
+  // |outstanding_requests_| map. This method is called when all changes have
+  // been acquired, or when the wait time expires (whichever is sooner).
+  static void Unregister(int sequence_number) {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+    RequestContextMap::iterator it =
+        outstanding_requests_.Get().find(sequence_number);
+    if (it == outstanding_requests_.Get().end())
+      return;
+
+    RequestContext* request = it->second;
+    DCHECK(sequence_number == request->sequence_number_);
+    bool received_process_group_count = request->received_process_group_count_;
+    int unresponsive_processes = request->processes_pending_;
+
+    delete it->second;
+    outstanding_requests_.Get().erase(it);
+
+    UMA_HISTOGRAM_BOOLEAN("Profiling.ReceivedProcessGroupCount",
+                          received_process_group_count);
+    UMA_HISTOGRAM_COUNTS("Profiling.PendingProcessNotResponding",
+                         unresponsive_processes);
+  }
+
+
+  // Delete all the entries in |outstanding_requests_| map.
+  static void OnShutdown() {
+    // Just in case we have any pending tasks, clear them out.
+    while (!outstanding_requests_.Get().empty()) {
+      RequestContextMap::iterator it = outstanding_requests_.Get().begin();
+      delete it->second;
+      outstanding_requests_.Get().erase(it);
+    }
+  }
+
+  // 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_;
+
+  // Indicates if we have received all pending processes count.
+  bool received_process_group_count_;
+
+  // The number of pending processes (browser, all renderer processes and
+  // browser child processes) that have not yet responded to requests.
+  int processes_pending_;
+
+  // Map of all outstanding RequestContexts, from sequence_number_ to
+  // RequestContext.
+  static base::LazyInstance<RequestContextMap> outstanding_requests_;
+};
+
 // Negative numbers are never used as sequence numbers.  We explicitly pick a
 // negative number that is "so negative" that even when we add one (as is done
 // when we generated the next sequence number) that it will still be negative.
@@ -30,32 +162,29 @@
 // territory.
 static const int kNeverUsableSequenceNumber = -2;
 
+// TrackingSynchronizer methods and members.
+//
+// static
+TrackingSynchronizer* TrackingSynchronizer::tracking_synchronizer_ = NULL;
+
 TrackingSynchronizer::TrackingSynchronizer()
     : last_used_sequence_number_(kNeverUsableSequenceNumber) {
   DCHECK(tracking_synchronizer_ == NULL);
   tracking_synchronizer_ = this;
+  content::ProfilerController::GetInstance()->Register(this);
 }
 
 TrackingSynchronizer::~TrackingSynchronizer() {
+  content::ProfilerController::GetInstance()->Unregister(this);
+
   // Just in case we have any pending tasks, clear them out.
-  while (!outstanding_requests_.empty()) {
-    RequestContextMap::iterator it = outstanding_requests_.begin();
-    delete it->second;
-    outstanding_requests_.erase(it);
-  }
+  RequestContext::OnShutdown();
 
   tracking_synchronizer_ = NULL;
 }
 
 // static
-TrackingSynchronizer* TrackingSynchronizer::CurrentSynchronizer() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DCHECK(tracking_synchronizer_ != NULL);
-  return tracking_synchronizer_;
-}
-
-// static
-void TrackingSynchronizer::FetchTrackingDataAsynchronously(
+void TrackingSynchronizer::FetchProfilerDataAsynchronously(
     const base::WeakPtr<ProfilerUI>& callback_object) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
@@ -72,133 +201,56 @@
   // as a watchdog, to cancel the requests for non-responsive processes.
   BrowserThread::PostDelayedTask(
       BrowserThread::UI, FROM_HERE,
-      NewRunnableMethod(
-          current_synchronizer,
-          &TrackingSynchronizer::ForceTrackingSynchronizationDoneCallback,
-          sequence_number),
+      base::Bind(&RequestContext::Unregister, sequence_number),
       60000);
 }
 
-// static
-void TrackingSynchronizer::SetTrackingStatus(bool enable) {
-  // To iterate over all processes, or to send messages to the hosts, we need
-  // to be on the UI thread.
+void TrackingSynchronizer::OnPendingProcesses(int sequence_number,
+                                              int pending_processes,
+                                              bool end) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  for (content::RenderProcessHost::iterator it(
-          content::RenderProcessHost::AllHostsIterator());
-       !it.IsAtEnd(); it.Advance()) {
-    content::RenderProcessHost* render_process_host = it.GetCurrentValue();
-    DCHECK(render_process_host);
-    // Ignore processes that don't have a connection, such as crashed tabs.
-    if (!render_process_host->HasConnection())
-      continue;
-
-    render_process_host->Send(new ChromeViewMsg_SetTrackingStatus(enable));
-  }
-}
-
-// static
-void TrackingSynchronizer::IsTrackingEnabled(int process_id) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  // To find the process, or to send messages to the hosts, we need to be on the
-  // UI thread.
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(
-          &TrackingSynchronizer::SetTrackingStatusInProcess, process_id));
-}
-
-// static
-void TrackingSynchronizer::SetTrackingStatusInProcess(int process_id) {
-  // To find the process, or to send messages to the hosts, we need to be on the
-  // UI thread.
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  bool enable = tracked_objects::ThreadData::tracking_status();
-
-  content::RenderProcessHost* process =
-      content::RenderProcessHost::FromID(process_id);
-  // Ignore processes that don't have a connection, such as crashed tabs.
-  if (!process || !process->HasConnection())
+  RequestContext* request = RequestContext::GetRequestContext(sequence_number);
+  if (!request)
     return;
-  process->Send(new ChromeViewMsg_SetTrackingStatus(enable));
+  request->AddProcessesPending(pending_processes);
+  request->SetReceivedProcessGroupCount(end);
+  request->DeleteIfAllDone();
 }
 
-// static
-void TrackingSynchronizer::DeserializeTrackingList(
+void TrackingSynchronizer::OnProfilerDataCollected(
     int sequence_number,
-    const std::string& tracking_data,
-    content::ProcessType process_type) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(
-          &TrackingSynchronizer::DeserializeTrackingListOnUI,
-          sequence_number, tracking_data, process_type));
-}
-
-// static
-void TrackingSynchronizer::DeserializeTrackingListOnUI(
-    int sequence_number,
-    const std::string& tracking_data,
-    content::ProcessType process_type) {
+    base::DictionaryValue* profiler_data) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  TrackingSynchronizer* current_synchronizer = CurrentSynchronizer();
-  if (current_synchronizer == NULL)
+  RequestContext* request = RequestContext::GetRequestContext(sequence_number);
+  if (!request)
     return;
 
-  base::Value* value =
-      base::JSONReader().JsonToValue(tracking_data, false, true);
-  DCHECK(value->GetType() == base::Value::TYPE_DICTIONARY);
-  base::DictionaryValue* dictionary_value =
-      static_cast<DictionaryValue*>(value);
-  dictionary_value->SetString(
-      "process_type", content::GetProcessTypeNameInEnglish(process_type));
-
-  current_synchronizer->DecrementPendingProcessesAndSendData(
-      sequence_number, dictionary_value);
+  DecrementPendingProcessesAndSendData(sequence_number, profiler_data);
 }
 
 int TrackingSynchronizer::RegisterAndNotifyAllProcesses(
     const base::WeakPtr<ProfilerUI>& callback_object) {
-  // To iterate over all processes, or to send messages to the hosts, we need
-  // to be on the UI thread.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   int sequence_number = GetNextAvailableSequenceNumber();
 
-  // Initialize processes_pending with one because we are going to send
-  // browser's ThreadData.
-  RequestContext* request = new RequestContext(
-      callback_object, sequence_number, 1, TimeTicks::Now());
-  outstanding_requests_[sequence_number] = request;
+  RequestContext* request =
+    RequestContext::Register(sequence_number, callback_object);
 
-  DCHECK_GT(request->processes_pending_, 0);
-  for (content::RenderProcessHost::iterator it(
-          content::RenderProcessHost::AllHostsIterator());
-       !it.IsAtEnd(); it.Advance()) {
-    content::RenderProcessHost* render_process_host = it.GetCurrentValue();
-    DCHECK(render_process_host);
-    // Ignore processes that don't have a connection, such as crashed tabs.
-    if (!render_process_host->HasConnection())
-      continue;
+  // Increment pending process count for sending browser's profiler data.
+  request->IncrementProcessesPending();
 
-    ++request->processes_pending_;
-    if (!render_process_host->Send(
-        new ChromeViewMsg_GetRendererTrackedData(sequence_number))) {
-      DecrementPendingProcesses(sequence_number);
-    }
-  }
+  // Get profiler data from renderer and browser child processes.
+  content::ProfilerController::GetInstance()->GetProfilerData(sequence_number);
 
-  // Get the ThreadData for the browser process and send it back.
+  // Send profiler_data from browser process.
   base::DictionaryValue* value = tracked_objects::ThreadData::ToValue();
   const std::string process_type =
       content::GetProcessTypeNameInEnglish(content::PROCESS_TYPE_BROWSER);
   value->SetString("process_type", process_type);
   value->SetInteger("process_id", base::GetCurrentProcId());
-  DCHECK_GT(request->processes_pending_, 0);
   DecrementPendingProcessesAndSendData(sequence_number, value);
 
   return sequence_number;
@@ -209,17 +261,12 @@
     base::DictionaryValue* value) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  RequestContextMap::iterator it =
-      outstanding_requests_.find(sequence_number);
-  if (it == outstanding_requests_.end()) {
+  RequestContext* request = RequestContext::GetRequestContext(sequence_number);
+  if (!request) {
     delete value;
     return;
   }
 
-  RequestContext* request = NULL;
-  request = it->second;
-  DCHECK(sequence_number == request->sequence_number_);
-
   if (value && request->callback_object_) {
     // Transfers ownership of |value| to |callback_object_|.
     request->callback_object_->ReceivedData(value);
@@ -227,37 +274,11 @@
     delete value;
   }
 
-  if (--request->processes_pending_ <= 0)
-    ForceTrackingSynchronizationDoneCallback(sequence_number);
+  // Delete request if we have heard back from all child processes.
+  request->DecrementProcessesPending();
+  request->DeleteIfAllDone();
 }
 
-void TrackingSynchronizer::DecrementPendingProcesses(int sequence_number) {
-  DecrementPendingProcessesAndSendData(sequence_number, NULL);
-}
-
-void TrackingSynchronizer::ForceTrackingSynchronizationDoneCallback(
-    int sequence_number) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  int unresponsive_processes;
-  RequestContextMap::iterator it =
-      outstanding_requests_.find(sequence_number);
-  if (it == outstanding_requests_.end())
-    return;
-
-  RequestContext* request = it->second;
-
-  DCHECK(sequence_number == request->sequence_number_);
-
-  unresponsive_processes = request->processes_pending_;
-
-  delete it->second;
-  outstanding_requests_.erase(it);
-
-  UMA_HISTOGRAM_COUNTS("Tracking.ProcessNotRespondingAsynchronous",
-                       unresponsive_processes);
-}
-
 int TrackingSynchronizer::GetNextAvailableSequenceNumber() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
@@ -270,6 +291,14 @@
 }
 
 // static
-TrackingSynchronizer* TrackingSynchronizer::tracking_synchronizer_ = NULL;
+TrackingSynchronizer* TrackingSynchronizer::CurrentSynchronizer() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(tracking_synchronizer_ != NULL);
+  return tracking_synchronizer_;
+}
 
+// static
+base::LazyInstance<RequestContext::RequestContextMap>
+    RequestContext::outstanding_requests_ = LAZY_INSTANCE_INITIALIZER;
+
 }  // namespace chrome_browser_metrics