Update task tracking to not depend on message_loop_ singleton

base/tracked_objects.h

Index: base/tracked_objects.h
===================================================================
--- base/tracked_objects.h	(revision 104925)
+++ base/tracked_objects.h	(working copy)
@@ -65,7 +65,10 @@
 // addition, the birth time is also recorded and used to later evaluate the
 // lifetime duration of the whole Task.  As a result of the above embedding, we
 // can find out a Task's location of birth, and thread of birth, without using
-// any locks, as all that data is constant across the life of the process.
+// any locks, as all that data is constant across the life of the process. We
+// currently over-write the birth time with the time at which a Run() of the

[awong, 2011/10/14 23:29:02]

over-write -> overwrite

[jar (doing other things), 2011/10/15 15:11:33]

Done.

+// task begins, so that we can calculate execution time independendent of
+// queueuing time (time spent in delayed task queues, or regular queues).
 //
 // This can also be done for any other object as well by calling
 // TallyABirthIfActive() and TallyADeathIfActive() as appropriate.
@@ -81,7 +84,7 @@
 // carefully accumulated.  That tallying wrties into slots (members) in a
 // collection of DeathData instances.  For each birth place Location that is
 // destroyed on a thread, there is a DeathData instance to record the additional
-// death count, as well as accumulate the lifetime duration of the instance as
+// death count, as well as accumulate the Run()time duration of the instance as
 // it is destroyed (dies).  By maintaining a single place to aggregate this
 // addition *only* for the given thread, we avoid the need to lock such
 // DeathData instances.
@@ -213,19 +216,20 @@
 class BASE_EXPORT DeathData {
  public:
   // Default initializer.
-  DeathData() : count_(0), square_duration_(0) {}
+  DeathData() : count_(0) {}
 
   // When deaths have not yet taken place, and we gather data from all the
   // threads, we create DeathData stats that tally the number of births without
   // a corrosponding death.
-  explicit DeathData(int count) : count_(count), square_duration_(0) {}
+  explicit DeathData(int count) : count_(count) {}
 
+  // Update stats for a task destruction (death) that had a Run() time of
+  // |duration|.
   void RecordDeath(const base::TimeDelta& duration);
 
   // Metrics accessors.
   int count() const { return count_; }
   base::TimeDelta life_duration() const { return life_duration_; }
-  int64 square_duration() const { return square_duration_; }
   int AverageMsDuration() const;
   double StandardDeviation() const;
 
@@ -239,9 +243,8 @@
   void Clear();
 
  private:
-  int count_;                // Number of destructions.
-  base::TimeDelta life_duration_;    // Sum of all lifetime durations.
-  int64 square_duration_;  // Sum of squares in milliseconds.
+  int count_;                      // Number of destructions.
+  base::TimeDelta life_duration_;  // Sum of all Run()time durations.
 };
 
 //------------------------------------------------------------------------------
@@ -270,7 +273,6 @@
 
   int count() const { return death_data_.count(); }
   base::TimeDelta life_duration() const { return death_data_.life_duration(); }
-  int64 square_duration() const { return death_data_.square_duration(); }
   int AverageMsDuration() const { return death_data_.AverageMsDuration(); }
 
   void Write(std::string* output) const;
@@ -472,7 +474,7 @@
   typedef std::map<Location, Births*> BirthMap;
   typedef std::map<const Births*, DeathData> DeathMap;
 
-  ThreadData();
+  explicit ThreadData(const char* suggested_name);
   ~ThreadData();
 
   // Using Thread Local Store, find the current instance for collecting data.
@@ -480,7 +482,7 @@
   // this thread.
   // If shutdown has already started, and we don't yet have an instance, then
   // return null.
-  static ThreadData* current();
+  static ThreadData* FactoryGet(const char* suggested_name);

[awong, 2011/10/14 23:29:02]

I thought the general pattern for singleton-ish getters was just to call this
ThreadData* Get().

FactoryGet() makes me think you're getting a factory.

If we use the MessageLoopProxy style convention, we'd just leave this as
"current()"

BTW, what happens if you call it with different suggested_names twice in one
thread?  Would it be better to just have a InitForThread() function separate
from the current() call?

[jar (doing other things), 2011/10/15 15:11:33]

Done.

On 2011/10/14 23:29:02, awong wrote:

 
   // For a given (unescaped) about:tracking query, develop resulting HTML, and
   // append to output.
@@ -496,22 +498,31 @@
   Births* TallyABirth(const Location& location);
 
   // Find a place to record a death on this thread.
-  void TallyADeath(const Births& lifetimes, const base::TimeDelta& duration);
+  void TallyADeath(const Births& the_birth, const base::TimeDelta& duration);
 
   // Helper methods to only tally if the current thread has tracking active.
   //
   // TallyABirthIfActive will returns NULL if the birth cannot be tallied.
   static Births* TallyABirthIfActive(const Location& location);
-  static void TallyADeathIfActive(const Births* lifetimes,
-                                  const base::TimeDelta& duration);
 
+  // Record the end of a timed run of an object.  The |the_birth| is the record
+  // for the instance, the |time_posted| and |start_of_run| are times of posting
+  // into a message loop queue, and of starting to perform the run of the task.
+  // Implied is that the run just (Now()) ended.  The current_message_loop is
+  // optional, and only used in DEBUG mode (when supplied) to verify that the
+  // ThreadData has a thread name that does indeed match the given loop's
+  // associated thread name (in RELEASE mode, its use is compiled away).
+  static void TallyADeathIfActive(const Births* the_birth,
+                                  const base::TimeTicks& time_posted,
+                                  const base::TimeTicks& start_of_run,
+                                  const MessageLoop* current_message_loop);
+
   // (Thread safe) Get start of list of instances.
   static ThreadData* first();
   // Iterate through the null terminated list of instances.
   ThreadData* next() const { return next_; }
 
-  MessageLoop* message_loop() const { return message_loop_; }
-  const std::string ThreadName() const;
+  const std::string thread_name() const { return thread_name_; }
 
   // Using our lock, make a copy of the specified maps.  These calls may arrive
   // from non-local threads, and are used to quickly scan data from all threads
@@ -540,19 +551,11 @@
   static bool StartTracking(bool status);
   static bool IsActive();
 
-#ifdef OS_WIN
-  // WARNING: ONLY call this function when all MessageLoops are still intact for
-  // all registered threads.  IF you call it later, you will crash.
-  // Note: You don't need to call it at all, and you can wait till you are
-  // single threaded (again) to do the cleanup via
-  // ShutdownSingleThreadedCleanup().
-  // Start the teardown (shutdown) process in a multi-thread mode by disabling
-  // further additions to thread database on all threads.  First it makes a
-  // local (locked) change to prevent any more threads from registering.  Then
-  // it Posts a Task to all registered threads to be sure they are aware that no
-  // more accumulation can take place.
-  static void ShutdownMultiThreadTracking();
-#endif
+  // Provide a time function that does nothing (runs fast) when we don't have
+  // the profiler enabled.  It will generally be optimized away when it is
+  // ifdef'ed to be small enough (allowing the profiler to be "compiled out" of
+  // the code).
+  static base::TimeTicks Now();
 
   // WARNING: ONLY call this function when you are running single threaded
   // (again) and all message loops and threads have terminated.  Until that
@@ -570,11 +573,6 @@
     SHUTDOWN,
   };
 
-#if defined(OS_WIN)
-  class ThreadSafeDownCounter;
-  class RunTheStatic;
-#endif
-
   // Each registered thread is called to set status_ to SHUTDOWN.
   // This is done redundantly on every registered thread because it is not
   // protected by a mutex.  Running on all threads guarantees we get the
@@ -600,11 +598,15 @@
   // data).
   ThreadData* next_;
 
-  // The message loop where tasks needing to access this instance's private data
-  // should be directed.  Since some threads have no message loop, some
-  // instances have data that can't be (safely) modified externally.
-  MessageLoop* message_loop_;
+  // The name of the thread that is being recorded.  If this is a worker thread,
+  // or has no message_loop, then this string is empty.
+  std::string thread_name_;
 
+  // A sequential number indicating when this thread context was created. If
+  // the thread_name_ is empty, then this values will be used to form a unique
+  // name.
+  int thread_number_;
+
   // A map used on each thread to keep track of Births on this thread.
   // This map should only be accessed on the thread it was constructed on.
   // When a snapshot is needed, this structure can be locked in place for the
@@ -625,6 +627,10 @@
   // writing is only done from this thread.
   mutable base::Lock lock_;
 
+  // The next available thread number.  This should only be accessed when the
+  // list_lock_ is held.
+  static int thread_number_counter;
+
   DISALLOW_COPY_AND_ASSIGN(ThreadData);
 };