Delivering the FIRST_NONEMPTY_PAINT phase changing event to base/

base/tracked_objects.h

 // Copyright (c) 2012 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_TRACKED_OBJECTS_H_
 #define BASE_TRACKED_OBJECTS_H_
 
 #include <map>
 #include <set>
 #include <stack>
@@ skipping 228 matching lines @@
 
 class BASE_EXPORT Births: public BirthOnThread {
  public:
   Births(const Location& location, const ThreadData& current);
 
   int birth_count() const;
 
   // When we have a birth we update the count for this birthplace.
   void RecordBirth();
 
+  // Subtracts a value from the birth count.
+  void SubtractBirths(int count);
+
  private:
   // The number of births on this thread for our location_.
   int birth_count_;
 
   DISALLOW_COPY_AND_ASSIGN(Births);
 };
 
 //------------------------------------------------------------------------------
 // Basic info summarizing multiple destructions of a tracked object with a
 // single birthplace (fixed Location).  Used both on specific threads, and also
@@ skipping 17 matching lines @@
 
   // Metrics accessors, used only for serialization and in tests.
   int count() const;
   int32 run_duration_sum() const;
   int32 run_duration_max() const;
   int32 run_duration_sample() const;
   int32 queue_duration_sum() const;
   int32 queue_duration_max() const;
   int32 queue_duration_sample() const;
 
-  // Reset all tallies to zero. This is used as a hack on realtime data.
+  // Reset all tallies to zero.
   void Clear();
 
  private:
   // Members are ordered from most regularly read and updated, to least
   // frequently used.  This might help a bit with cache lines.
   // Number of runs seen (divisor for calculating averages).
   int count_;
   // Basic tallies, used to compute averages.
   int32 run_duration_sum_;
   int32 queue_duration_sum_;
@@ skipping 52 matching lines @@
 
 struct ProcessDataPhaseSnapshot;
 struct ProcessDataSnapshot;
 class BASE_EXPORT TaskStopwatch;
 
 // Map from profiling phase number to the process-wide snapshotted
 // representation of the list of ThreadData objects that died during the given
 // phase.
 typedef std::map<int, ProcessDataPhaseSnapshot> PhasedProcessDataSnapshotMap;
 
+// Results of resetting death counts to 0. This is a map from the Births pointer
+// to the count of deaths (for tasks with this Births) that were set to 0 by
+// resetting.
+typedef std::map<const Births*, int> DeathResetResults;
+
 class BASE_EXPORT ThreadData {
  public:
   // Current allowable states of the tracking system.  The states can vary
   // between ACTIVE and DEACTIVATED, but can never go back to UNINITIALIZED.
   enum Status {
     UNINITIALIZED,              // PRistine, link-time state before running.
     DORMANT_DURING_TESTS,       // Only used during testing.
     DEACTIVATED,                // No longer recording profiling.
     PROFILING_ACTIVE,           // Recording profiles (no parent-child links).
     PROFILING_CHILDREN_ACTIVE,  // Fully active, recording parent-child links.
@@ skipping 12 matching lines @@
   // only used by the message loop, which has a well defined thread name.
   static void InitializeThreadContext(const std::string& suggested_name);
 
   // Using Thread Local Store, find the current instance for collecting data.
   // If an instance does not exist, construct one (and remember it for use on
   // this thread.
   // This may return NULL if the system is disabled for any reason.
   static ThreadData* Get();
 
   // Fills |process_data_snapshot| with phased snapshots of all profiling
-  // phases, including the current one.
-  static void Snapshot(ProcessDataSnapshot* process_data_snapshot);
+  // phases, including the current one, identified by |current_profiling_phase|.
+  // |current_profiling_phase| is necessary because a child process can start
+  // after several phase-changing events, so it needs to receive the current
+  // phase number from the browser process to fill the correct entry for the
+  // current phase in the |process_data_snapshot| map.
+  static void Snapshot(int current_profiling_phase,
+                       ProcessDataSnapshot* process_data_snapshot);
+
+  // Called when the current profiling phase, identified by |profiling_phase|,
+  // ends.
+  // |profiling_phase| is necessary because a child process can start after
+  // several phase-changing events, so it needs to receive the phase number from
+  // the browser process to fill the correct entry in the
+  // completed_phases_snapshots_ map.
+  static void OnProfilingPhaseCompletion(int profiling_phase);
 
   // Finds (or creates) a place to count births from the given location in this
   // thread, and increment that tally.
   // TallyABirthIfActive will returns NULL if the birth cannot be tallied.
   static Births* TallyABirthIfActive(const Location& location);
 
   // Records the end of a timed run of an object.  The |completed_task| contains
   // a pointer to a Births, the time_posted, and a delayed_start_time if any.
   // The |start_of_run| indicates when we started to perform the run of the
   // task.  The delayed_start_time is non-null for tasks that were posted as
   // delayed tasks, and it indicates when the task should have run (i.e., when
   // it should have posted out of the timer queue, and into the work queue.
   // The |end_of_run| was just obtained by a call to Now() (just after the task
   // finished). It is provided as an argument to help with testing.
   static void TallyRunOnNamedThreadIfTracking(
       const base::TrackingInfo& completed_task,
       const TaskStopwatch& stopwatch);
 
   // Record the end of a timed run of an object.  The |birth| is the record for
   // the instance, the |time_posted| records that instant, which is presumed to
   // be when the task was posted into a queue to run on a worker thread.
   // The |start_of_run| is when the worker thread started to perform the run of
   // the task.
   // The |end_of_run| was just obtained by a call to Now() (just after the task
   // finished).
-  static void TallyRunOnWorkerThreadIfTracking(const Births* birth,
+  static void TallyRunOnWorkerThreadIfTracking(const Births* births,
                                                const TrackedTime& time_posted,
                                                const TaskStopwatch& stopwatch);
 
   // Record the end of execution in region, generally corresponding to a scope
   // being exited.
-  static void TallyRunInAScopedRegionIfTracking(const Births* birth,
+  static void TallyRunInAScopedRegionIfTracking(const Births* births,
                                                 const TaskStopwatch& stopwatch);
 
   const std::string& thread_name() const { return thread_name_; }
 
   // Initializes all statics if needed (this initialization call should be made
   // while we are single threaded). Returns false if unable to initialize.
   static bool Initialize();
 
   // Sets internal status_.
   // If |status| is false, then status_ is set to DEACTIVATED.
@@ skipping 75 matching lines @@
   static ThreadData* first();
 
   // Iterate through the null terminated list of ThreadData instances.
   ThreadData* next() const;
 
 
   // In this thread's data, record a new birth.
   Births* TallyABirth(const Location& location);
 
   // Find a place to record a death on this thread.
-  void TallyADeath(const Births& birth,
+  void TallyADeath(const Births& births,
                    int32 queue_duration,
                    const TaskStopwatch& stopwatch);
 
   // Snapshot (under a lock) the profiled data for the tasks in each ThreadData
   // instance.  Also updates the |birth_counts| tally for each task to keep
-  // track of the number of living instances of the task.
+  // track of the number of living instances of the task. If |reset| is true,
+  // remove all recorded deaths.
   static void SnapshotAllExecutedTasks(
+      bool reset,

[jar (doing other things), 2015/04/01 17:10:25]

This is totally unsafe, and will instigate errors as large as the tally of
births, due to races.

[vadimt, 2015/04/06 23:25:12]

Done.

       ProcessDataPhaseSnapshot* process_data_phase,
       BirthCountMap* birth_counts);
 
   // Fills |process_data_phase| with all the recursive results in our process.
+  // If |reset| is true, remove all recorded deaths.
   static void SnapshotCurrentPhase(
+      bool reset,
       ProcessDataPhaseSnapshot* process_data_phase);
 
   // Snapshots (under a lock) the profiled data for the tasks for this thread
   // and writes all of the executed tasks' data -- i.e. the data for the tasks
   // with with entries in the death_map_ -- into |process_data_phase|.  Also
   // updates the |birth_counts| tally for each task to keep track of the number
   // of living instances of the task -- that is, each task maps to the number of
-  // births for the task that have not yet been balanced by a death.
+  // births for the task that have not yet been balanced by a death. If
+  // |death_reset_results| is not null, store current death counts in it and

[jar (doing other things), 2015/04/01 17:10:25]

You can't get away with doing atomic operation so casually, as a race (without a
lock) will result in garbage values (delta as large as the size of the current
tally generally... and perhaps it will actually be worse).

[vadimt, 2015/04/06 23:25:12]

Done.

+  // remove all recorded deaths.
   void SnapshotExecutedTasks(ProcessDataPhaseSnapshot* process_data_phase,
+                             DeathResetResults* death_reset_results,
                              BirthCountMap* birth_counts);
 
   // Using our lock, make a copy of the specified maps.  This call may be made
   // on  non-local threads, which necessitate the use of the lock to prevent
-  // the map(s) from being reallocated while they are copied.
+  // the map(s) from being reallocated while they are copied. If
+  // |death_reset_results| is not null, store current death counts in it and
+  // remove all recorded deaths.
   void SnapshotMaps(BirthMap* birth_map,
                     DeathMap* death_map,
+                    DeathResetResults* death_reset_results,
                     ParentChildSet* parent_child_set);
 
+  // Using our lock, decrease births counts owned by this thread after a death
+  // data's reset.
+  // |death_reset_results| is the result of the cross-threads death count reset
+  // operation that took place before calling this method. For each Birth owned
+  // by this ThreadData, the method will subtract from its birth count the total
+  // number of deaths that were 'forgotten' by resetting death counts to 0.
+  void SubtractDeathResultsFromBirths(
+      const DeathResetResults& death_reset_results);
+
   // This method is called by the TLS system when a thread terminates.
   // The argument may be NULL if this thread has never tracked a birth or death.
   static void OnThreadTermination(void* thread_data);
 
   // This method should be called when a worker thread terminates, so that we
   // can save all the thread data into a cache of reusable ThreadData instances.
   void OnThreadTerminationCleanup();
 
   // Cleans up data structures, and returns statics to near pristine (mostly
   // uninitialized) state.  If there is any chance that other threads are still
@@ skipping 44 matching lines @@
 
   // Protection for access to all_thread_data_list_head_, and to
   // unregistered_thread_data_pool_.  This lock is leaked at shutdown.
   // The lock is very infrequently used, so we can afford to just make a lazy
   // instance and be safe.
   static base::LazyInstance<base::Lock>::Leaky list_lock_;
 
   // We set status_ to SHUTDOWN when we shut down the tracking service.
   static Status status_;
 
+  // Process data snapshots for completed profiling phases.
+  static base::LazyInstance<PhasedProcessDataSnapshotMap>
+      completed_phases_snapshots_;
+
   // Link to next instance (null terminated list). Used to globally track all
   // registered instances (corresponds to all registered threads where we keep
   // data).
   ThreadData* next_;
 
   // Pointer to another ThreadData instance for a Worker-Thread that has been
   // retired (its thread was terminated).  This value is non-NULL only for a
   // retired ThreadData associated with a Worker-Thread.
   ThreadData* next_retired_worker_;
 
@@ skipping 158 matching lines @@
   ProcessDataSnapshot();
   ~ProcessDataSnapshot();
 
   PhasedProcessDataSnapshotMap phased_process_data_snapshots;
   base::ProcessId process_id;
 };
 
 }  // namespace tracked_objects
 
 #endif  // BASE_TRACKED_OBJECTS_H_