Enable timeline visualizations of object transfers. (#3255)

* Plot object transfers.

* Linting

python/ray/experimental/state.py

@@ -584,46 +584,14 @@ class GlobalState(object):
             for component_id in component_identifiers_binary
         }
 
-    def chrome_tracing_dump(self,
+    def _seconds_to_microseconds(self, time_in_seconds):
-                            include_task_data=False,
+        """A helper function for converting seconds to microseconds."""
-                            filename=None,
+        time_in_microseconds = 10**6 * time_in_seconds
-                            open_browser=False):
+        return time_in_microseconds
-        """Return a list of profiling events that can viewed as a timeline.
-
-        To view this information as a timeline, simply dump it as a json file
-        using json.dumps, and then load go to chrome://tracing in the Chrome
-        web browser and load the dumped file. Make sure to enable "Flow events"
-        in the "View Options" menu.
-
-        Args:
-            include_task_data: If true, we will include more task metadata such
-                as the task specifications in the json.
-            filename: If a filename is provided, the timeline is dumped to that
-                file.
-            open_browser: If true, we will attempt to automatically open the
-                timeline visualization in Chrome.
-
-        Returns:
-            If filename is not provided, this returns a list of profiling
-                events. Each profile event is a dictionary.
-        """
-        # TODO(rkn): Support including the task specification data in the
-        # timeline.
-        # TODO(rkn): This should support viewing just a window of time or a
-        # limited number of events.
-
-        if include_task_data:
-            raise NotImplementedError("This flag has not been implented yet.")
-
-        if open_browser:
-            raise NotImplementedError("This flag has not been implented yet.")
-
-        profile_table = self.profile_table()
-        all_events = []
 
     # Colors are specified at
     # https://github.com/catapult-project/catapult/blob/master/tracing/tracing/base/color_scheme.html.  # noqa: E501
-        default_color_mapping = defaultdict(
+    _default_color_mapping = defaultdict(
         lambda: "generic_work", {
             "worker_idle": "cq_build_abandoned",
             "task": "rail_response",
@@ -639,11 +607,74 @@ class GlobalState(object):
             "register_remote_function": "detailed_memory_dump",
         })
 
-        def seconds_to_microseconds(time_in_seconds):
+    # These colors are for use in Chrome tracing.
-            time_in_microseconds = 10**6 * time_in_seconds
+    _chrome_tracing_colors = [
-            return time_in_microseconds
+        "thread_state_uninterruptible",
+        "thread_state_iowait",
+        "thread_state_running",
+        "thread_state_runnable",
+        "thread_state_sleeping",
+        "thread_state_unknown",
+        "background_memory_dump",
+        "light_memory_dump",
+        "detailed_memory_dump",
+        "vsync_highlight_color",
+        "generic_work",
+        "good",
+        "bad",
+        "terrible",
+        # "black",
+        # "grey",
+        # "white",
+        "yellow",
+        "olive",
+        "rail_response",
+        "rail_animation",
+        "rail_idle",
+        "rail_load",
+        "startup",
+        "heap_dump_stack_frame",
+        "heap_dump_object_type",
+        "heap_dump_child_node_arrow",
+        "cq_build_running",
+        "cq_build_passed",
+        "cq_build_failed",
+        "cq_build_abandoned",
+        "cq_build_attempt_runnig",
+        "cq_build_attempt_passed",
+        "cq_build_attempt_failed",
+    ]
+
+    def chrome_tracing_dump(self, filename=None):
+        """Return a list of profiling events that can viewed as a timeline.
+
+        To view this information as a timeline, simply dump it as a json file
+        by passing in "filename" or using using json.dump, and then load go to
+        chrome://tracing in the Chrome web browser and load the dumped file.
+        Make sure to enable "Flow events" in the "View Options" menu.
+
+        Args:
+            filename: If a filename is provided, the timeline is dumped to that
+                file.
+
+        Returns:
+            If filename is not provided, this returns a list of profiling
+                events. Each profile event is a dictionary.
+        """
+        # TODO(rkn): Support including the task specification data in the
+        # timeline.
+        # TODO(rkn): This should support viewing just a window of time or a
+        # limited number of events.
+
+        profile_table = self.profile_table()
+        all_events = []
 
         for component_id_hex, component_events in profile_table.items():
+            # Only consider workers and drivers.
+            component_type = component_events[0]["component_type"]
+            if component_type not in ["worker", "driver"]:
+                continue
+
             for event in component_events:
                 new_event = {
                     # The category of the event.
@@ -657,14 +688,14 @@ class GlobalState(object):
                     "tid": event["component_type"] + ":" +
                     event["component_id"],
                     # The start time in microseconds.
-                    "ts": seconds_to_microseconds(event["start_time"]),
+                    "ts": self._seconds_to_microseconds(event["start_time"]),
                     # The duration in microseconds.
-                    "dur": seconds_to_microseconds(event["end_time"] -
+                    "dur": self._seconds_to_microseconds(event["end_time"] -
                                                          event["start_time"]),
                     # What is this?
                     "ph": "X",
                     # This is the name of the color to display the box in.
-                    "cname": default_color_mapping[event["event_type"]],
+                    "cname": self._default_color_mapping[event["event_type"]],
                     # The extra user-defined data.
                     "args": event["extra_data"],
                 }
@@ -684,6 +715,97 @@ class GlobalState(object):
         else:
             return all_events
 
+    def chrome_tracing_object_transfer_dump(self, filename=None):
+        """Return a list of transfer events that can viewed as a timeline.
+
+        To view this information as a timeline, simply dump it as a json file
+        by passing in "filename" or using using json.dump, and then load go to
+        chrome://tracing in the Chrome web browser and load the dumped file.
+        Make sure to enable "Flow events" in the "View Options" menu.
+
+        Args:
+            filename: If a filename is provided, the timeline is dumped to that
+                file.
+
+        Returns:
+            If filename is not provided, this returns a list of profiling
+                events. Each profile event is a dictionary.
+        """
+        client_id_to_address = {}
+        for client_info in ray.global_state.client_table():
+            client_id_to_address[client_info["ClientID"]] = "{}:{}".format(
+                client_info["NodeManagerAddress"],
+                client_info["ObjectManagerPort"])
+
+        all_events = []
+
+        for key, items in self.profile_table().items():
+            # Only consider object manager events.
+            if items[0]["component_type"] != "object_manager":
+                continue
+
+            for event in items:
+                if event["event_type"] == "transfer_send":
+                    object_id, remote_client_id, _, _ = event["extra_data"]
+
+                elif event["event_type"] == "transfer_receive":
+                    object_id, remote_client_id, _, _ = event["extra_data"]
+
+                elif event["event_type"] == "receive_pull_request":
+                    object_id, remote_client_id = event["extra_data"]
+
+                else:
+                    assert False, "This should be unreachable."
+
+                # Choose a color by reading the first couple of hex digits of
+                # the object ID as an integer and turning that into a color.
+                object_id_int = int(object_id[:2], 16)
+                color = self._chrome_tracing_colors[object_id_int % len(
+                    self._chrome_tracing_colors)]
+
+                new_event = {
+                    # The category of the event.
+                    "cat": event["event_type"],
+                    # The string displayed on the event.
+                    "name": event["event_type"],
+                    # The identifier for the group of rows that the event
+                    # appears in.
+                    "pid": client_id_to_address[key],
+                    # The identifier for the row that the event appears in.
+                    "tid": client_id_to_address[remote_client_id],
+                    # The start time in microseconds.
+                    "ts": self._seconds_to_microseconds(event["start_time"]),
+                    # The duration in microseconds.
+                    "dur": self._seconds_to_microseconds(event["end_time"] -
+                                                         event["start_time"]),
+                    # What is this?
+                    "ph": "X",
+                    # This is the name of the color to display the box in.
+                    "cname": color,
+                    # The extra user-defined data.
+                    "args": event["extra_data"],
+                }
+                all_events.append(new_event)
+
+                # Add another box with a color indicating whether it was a send
+                # or a receive event.
+                if event["event_type"] == "transfer_send":
+                    additional_event = new_event.copy()
+                    additional_event["cname"] = "black"
+                    all_events.append(additional_event)
+                elif event["event_type"] == "transfer_receive":
+                    additional_event = new_event.copy()
+                    additional_event["cname"] = "grey"
+                    all_events.append(additional_event)
+                else:
+                    pass
+
+        if filename is not None:
+            with open(filename, "w") as outfile:
+                json.dump(all_events, outfile)
+        else:
+            return all_events
+
     def dump_catapult_trace(self,
                             path,
                             task_info,

src/ray/common/client_connection.cc

@@ -233,12 +233,12 @@ void ClientConnection<T>::ProcessMessage(const boost::system::error_code &error)
     read_type_ = static_cast<int64_t>(protocol::MessageType::DisconnectClient);
   }
 
-  uint64_t start_ms = current_time_ms();
+  int64_t start_ms = current_time_ms();
   message_handler_(shared_ClientConnection_from_this(), read_type_, read_message_.data());
-  uint64_t interval = current_time_ms() - start_ms;
+  int64_t interval = current_time_ms() - start_ms;
   if (interval > RayConfig::instance().handler_warning_timeout_ms()) {
     RAY_LOG(WARNING) << "[" << debug_label_ << "]ProcessMessage with type " << read_type_
-                     << " took " << interval << " ms ";
+                     << " took " << interval << " ms.";
   }
 }
 

src/ray/object_manager/object_manager.cc

@@ -283,6 +283,9 @@ void ObjectManager::PullEstablishConnection(const ObjectID &object_id,
 
 void ObjectManager::PullSendRequest(const ObjectID &object_id,
                                     std::shared_ptr<SenderConnection> &conn) {
+  // TODO(rkn): This would be a natural place to record a profile event
+  // indicating that a pull request was sent.
+
   flatbuffers::FlatBufferBuilder fbb;
   auto message = object_manager_protocol::CreatePullRequestMessage(
       fbb, fbb.CreateString(client_id_.binary()), fbb.CreateString(object_id.binary()));
@@ -311,6 +314,46 @@ void ObjectManager::HandlePushTaskTimeout(const ObjectID &object_id,
   }
 }
 
+void ObjectManager::HandleSendFinished(const ObjectID &object_id,
+                                       const ClientID &client_id, uint64_t chunk_index,
+                                       double start_time, double end_time,
+                                       ray::Status status) {
+  if (!status.ok()) {
+    // TODO(rkn): What do we want to do if the send failed?
+  }
+
+  ProfileEventT profile_event;
+  profile_event.event_type = "transfer_send";
+  profile_event.start_time = start_time;
+  profile_event.end_time = end_time;
+  // Encode the object ID, client ID, chunk index, and status as a json list,
+  // which will be parsed by the reader of the profile table.
+  profile_event.extra_data = "[\"" + object_id.hex() + "\",\"" + client_id.hex() + "\"," +
+                             std::to_string(chunk_index) + ",\"" + status.ToString() +
+                             "\"]";
+  profile_events_.push_back(profile_event);
+}
+
+void ObjectManager::HandleReceiveFinished(const ObjectID &object_id,
+                                          const ClientID &client_id, uint64_t chunk_index,
+                                          double start_time, double end_time,
+                                          ray::Status status) {
+  if (!status.ok()) {
+    // TODO(rkn): What do we want to do if the send failed?
+  }
+
+  ProfileEventT profile_event;
+  profile_event.event_type = "transfer_receive";
+  profile_event.start_time = start_time;
+  profile_event.end_time = end_time;
+  // Encode the object ID, client ID, chunk index, and status as a json list,
+  // which will be parsed by the reader of the profile table.
+  profile_event.extra_data = "[\"" + object_id.hex() + "\",\"" + client_id.hex() + "\"," +
+                             std::to_string(chunk_index) + ",\"" + status.ToString() +
+                             "\"]";
+  profile_events_.push_back(profile_event);
+}
+
 void ObjectManager::Push(const ObjectID &object_id, const ClientID &client_id) {
   if (local_objects_.count(object_id) == 0) {
     // Avoid setting duplicated timer for the same object and client pair.
@@ -355,12 +398,21 @@ void ObjectManager::Push(const ObjectID &object_id, const ClientID &client_id) {
     for (uint64_t chunk_index = 0; chunk_index < num_chunks; ++chunk_index) {
       send_service_.post([this, client_id, object_id, data_size, metadata_size,
                           chunk_index, connection_info]() {
+        double start_time = current_sys_time_seconds();
         // NOTE: When this callback executes, it's possible that the object
         // will have already been evicted. It's also possible that the
         // object could be in the process of being transferred to this
         // object manager from another object manager.
-        ExecuteSendObject(client_id, object_id, data_size, metadata_size, chunk_index,
+        ray::Status status = ExecuteSendObject(
-                          connection_info);
+            client_id, object_id, data_size, metadata_size, chunk_index, connection_info);
+
+        // Notify the main thread that we have finished sending the chunk.
+        main_service_->post(
+            [this, object_id, client_id, chunk_index, start_time, status]() {
+              double end_time = current_sys_time_seconds();
+              HandleSendFinished(object_id, client_id, chunk_index, start_time, end_time,
+                                 status);
+            });
       });
     }
   } else {
@@ -370,8 +422,8 @@ void ObjectManager::Push(const ObjectID &object_id, const ClientID &client_id) {
   }
 }
 
-void ObjectManager::ExecuteSendObject(const ClientID &client_id,
+ray::Status ObjectManager::ExecuteSendObject(
-                                      const ObjectID &object_id, uint64_t data_size,
+    const ClientID &client_id, const ObjectID &object_id, uint64_t data_size,
     uint64_t metadata_size, uint64_t chunk_index,
     const RemoteConnectionInfo &connection_info) {
   RAY_LOG(DEBUG) << "ExecuteSendObject " << client_id << " " << object_id << " "
@@ -390,6 +442,7 @@ void ObjectManager::ExecuteSendObject(const ClientID &client_id,
       CheckIOError(status, "Push");
     }
   }
+  return status;
 }
 
 ray::Status ObjectManager::SendObjectHeaders(const ObjectID &object_id,
@@ -709,6 +762,14 @@ void ObjectManager::ReceivePullRequest(std::shared_ptr<TcpClientConnection> &con
   auto pr = flatbuffers::GetRoot<object_manager_protocol::PullRequestMessage>(message);
   ObjectID object_id = ObjectID::from_binary(pr->object_id()->str());
   ClientID client_id = ClientID::from_binary(pr->client_id()->str());
+
+  ProfileEventT profile_event;
+  profile_event.event_type = "receive_pull_request";
+  profile_event.start_time = current_sys_time_seconds();
+  profile_event.end_time = profile_event.start_time;
+  profile_event.extra_data = "[\"" + object_id.hex() + "\",\"" + client_id.hex() + "\"]";
+  profile_events_.push_back(profile_event);
+
   Push(object_id, client_id);
   conn->ProcessMessages();
 }
@@ -718,20 +779,28 @@ void ObjectManager::ReceivePushRequest(std::shared_ptr<TcpClientConnection> &con
   // Serialize.
   auto object_header =
       flatbuffers::GetRoot<object_manager_protocol::PushRequestMessage>(message);
-  ObjectID object_id = ObjectID::from_binary(object_header->object_id()->str());
+  const ObjectID object_id = ObjectID::from_binary(object_header->object_id()->str());
   uint64_t chunk_index = object_header->chunk_index();
   uint64_t data_size = object_header->data_size();
   uint64_t metadata_size = object_header->metadata_size();
   receive_service_.post([this, object_id, data_size, metadata_size, chunk_index, conn]() {
-    ExecuteReceiveObject(conn->GetClientID(), object_id, data_size, metadata_size,
+    double start_time = current_sys_time_seconds();
+    const ClientID client_id = conn->GetClientID();
+    auto status = ExecuteReceiveObject(client_id, object_id, data_size, metadata_size,
                                        chunk_index, *conn);
+    // Notify the main thread that we have finished receiving the object.
+    main_service_->post([this, object_id, client_id, chunk_index, start_time, status]() {
+      double end_time = current_sys_time_seconds();
+      HandleReceiveFinished(object_id, client_id, chunk_index, start_time, end_time,
+                            status);
+    });
+
   });
 }
 
-void ObjectManager::ExecuteReceiveObject(const ClientID &client_id,
+ray::Status ObjectManager::ExecuteReceiveObject(
-                                         const ObjectID &object_id, uint64_t data_size,
+    const ClientID &client_id, const ObjectID &object_id, uint64_t data_size,
-                                         uint64_t metadata_size, uint64_t chunk_index,
+    uint64_t metadata_size, uint64_t chunk_index, TcpClientConnection &conn) {
-                                         TcpClientConnection &conn) {
   RAY_LOG(DEBUG) << "ExecuteReceiveObject " << client_id << " " << object_id << " "
                  << chunk_index;
 
@@ -769,6 +838,8 @@ void ObjectManager::ExecuteReceiveObject(const ClientID &client_id,
   conn.ProcessMessages();
   RAY_LOG(DEBUG) << "ReceiveCompleted " << client_id_ << " " << object_id << " "
                  << "/" << config_.max_receives;
+
+  return chunk_status.second;
 }
 
 void ObjectManager::ReceiveFreeRequest(std::shared_ptr<TcpClientConnection> &conn,
@@ -820,4 +891,18 @@ void ObjectManager::SpreadFreeObjectRequest(const std::vector<ObjectID> &object_
   }
 }
 
+ProfileTableDataT ObjectManager::GetAndResetProfilingInfo() {
+  ProfileTableDataT profile_info;
+  profile_info.component_type = "object_manager";
+  profile_info.component_id = client_id_.binary();
+
+  for (auto const &profile_event : profile_events_) {
+    profile_info.profile_events.emplace_back(new ProfileEventT(profile_event));
+  }
+
+  profile_events_.clear();
+
+  return profile_info;
+}
+
 }  // namespace ray

src/ray/object_manager/object_manager.h

@@ -175,6 +175,12 @@ class ObjectManager : public ObjectManagerInterface {
   ///                   or send it to all the object stores.
   void FreeObjects(const std::vector<ObjectID> &object_ids, bool local_only);
 
+  /// Return profiling information and reset the profiling information.
+  ///
+  /// \return All profiling information that has accumulated since the last call
+  /// to this method.
+  ProfileTableDataT GetAndResetProfilingInfo();
+
  private:
   friend class TestObjectManager;
 
@@ -252,17 +258,55 @@ class ObjectManager : public ObjectManagerInterface {
 
   /// Asynchronously send a pull request via remote object manager connection.
   /// Executes on main_service_ thread.
+  ///
+  /// \param object_id The ID of the object request.
+  /// \param conn The connection to the remote object manager.
+  /// \return Void.
   void PullSendRequest(const ObjectID &object_id,
                        std::shared_ptr<SenderConnection> &conn);
 
   std::shared_ptr<SenderConnection> CreateSenderConnection(
       ConnectionPool::ConnectionType type, RemoteConnectionInfo info);
 
+  /// This is used to notify the main thread that the sending of a chunk has
+  /// completed.
+  ///
+  /// \param object_id The ID of the object that was sent.
+  /// \param client_id The ID of the client that the chunk was sent to.
+  /// \param chunk_index The index of the chunk.
+  /// \param start_time_us The time when the object manager began sending the
+  /// chunk.
+  /// \param end_time_us The time when the object manager finished sending the
+  /// chunk.
+  /// \param status The status of the send (e.g., did it succeed or fail).
+  /// \return Void.
+  void HandleSendFinished(const ObjectID &object_id, const ClientID &client_id,
+                          uint64_t chunk_index, double start_time_us, double end_time_us,
+                          ray::Status status);
+
+  /// This is used to notify the main thread that the receiving of a chunk has
+  /// completed.
+  ///
+  /// \param object_id The ID of the object that was received.
+  /// \param client_id The ID of the client that the chunk was received from.
+  /// \param chunk_index The index of the chunk.
+  /// \param start_time_us The time when the object manager began receiving the
+  /// chunk.
+  /// \param end_time_us The time when the object manager finished receiving the
+  /// chunk.
+  /// \param status The status of the receive (e.g., did it succeed or fail).
+  /// \return Void.
+  void HandleReceiveFinished(const ObjectID &object_id, const ClientID &client_id,
+                             uint64_t chunk_index, double start_time_us,
+                             double end_time_us, ray::Status status);
+
   /// Begin executing a send.
   /// Executes on send_service_ thread pool.
-  void ExecuteSendObject(const ClientID &client_id, const ObjectID &object_id,
+  ray::Status ExecuteSendObject(const ClientID &client_id, const ObjectID &object_id,
-                         uint64_t data_size, uint64_t metadata_size, uint64_t chunk_index,
+                                uint64_t data_size, uint64_t metadata_size,
+                                uint64_t chunk_index,
                                 const RemoteConnectionInfo &connection_info);
+
   /// This method synchronously sends the object id and object size
   /// to the remote object manager.
   /// Executes on send_service_ thread pool.
@@ -280,8 +324,9 @@ class ObjectManager : public ObjectManagerInterface {
   /// This will invoke the object receive on the receive_service_ thread pool.
   void ReceivePushRequest(std::shared_ptr<TcpClientConnection> &conn,
                           const uint8_t *message);
+
   /// Execute a receive on the receive_service_ thread pool.
-  void ExecuteReceiveObject(const ClientID &client_id, const ObjectID &object_id,
+  ray::Status ExecuteReceiveObject(const ClientID &client_id, const ObjectID &object_id,
                                    uint64_t data_size, uint64_t metadata_size,
                                    uint64_t chunk_index, TcpClientConnection &conn);
 
@@ -351,6 +396,10 @@ class ObjectManager : public ObjectManagerInterface {
       unfulfilled_push_requests_;
 
   std::unordered_map<ObjectID, PullRequest> pull_requests_;
+
+  /// Profiling events that are to be batched together and added to the profile
+  /// table in the GCS.
+  std::vector<ProfileEventT> profile_events_;
 };
 
 }  // namespace ray

src/ray/ray_config.h

@@ -12,7 +12,7 @@ class RayConfig {
 
   int64_t ray_protocol_version() const { return ray_protocol_version_; }
 
-  uint64_t handler_warning_timeout_ms() const { return handler_warning_timeout_ms_; }
+  int64_t handler_warning_timeout_ms() const { return handler_warning_timeout_ms_; }
 
   int64_t heartbeat_timeout_milliseconds() const {
     return heartbeat_timeout_milliseconds_;
@@ -147,7 +147,7 @@ class RayConfig {
 
   /// The duration that a single handler on the event loop can take before a
   /// warning is logged that the handler is taking too long.
-  uint64_t handler_warning_timeout_ms_;
+  int64_t handler_warning_timeout_ms_;
 
   /// The duration between heartbeats. These are sent by the plasma manager and
   /// local scheduler.

src/ray/raylet/node_manager.cc

@@ -50,6 +50,7 @@ NodeManager::NodeManager(boost::asio::io_service &io_service,
       gcs_client_(gcs_client),
       heartbeat_timer_(io_service),
       heartbeat_period_(std::chrono::milliseconds(config.heartbeat_period_ms)),
+      object_manager_profile_timer_(io_service),
       local_resources_(config.resource_config),
       local_available_resources_(config.resource_config),
       worker_pool_(config.num_initial_workers, config.num_workers_per_process,
@@ -174,6 +175,9 @@ ray::Status NodeManager::RegisterGcs() {
   // Start sending heartbeats to the GCS.
   last_heartbeat_at_ms_ = current_time_ms();
   Heartbeat();
+  // Start the timer that gets object manager profiling information and sends it
+  // to the GCS.
+  GetObjectManagerProfileInfo();
 
   return ray::Status::OK();
 }
@@ -280,6 +284,34 @@ void NodeManager::Heartbeat() {
   });
 }
 
+void NodeManager::GetObjectManagerProfileInfo() {
+  int64_t start_time_ms = current_time_ms();
+
+  auto profile_info = object_manager_.GetAndResetProfilingInfo();
+
+  if (profile_info.profile_events.size() > 0) {
+    flatbuffers::FlatBufferBuilder fbb;
+    auto message = CreateProfileTableData(fbb, &profile_info);
+    fbb.Finish(message);
+    auto profile_message = flatbuffers::GetRoot<ProfileTableData>(fbb.GetBufferPointer());
+
+    RAY_CHECK_OK(gcs_client_->profile_table().AddProfileEventBatch(*profile_message));
+  }
+
+  // Reset the timer.
+  object_manager_profile_timer_.expires_from_now(heartbeat_period_);
+  object_manager_profile_timer_.async_wait(
+      [this](const boost::system::error_code &error) {
+        RAY_CHECK(!error);
+        GetObjectManagerProfileInfo();
+      });
+
+  int64_t interval = current_time_ms() - start_time_ms;
+  if (interval > RayConfig::instance().handler_warning_timeout_ms()) {
+    RAY_LOG(WARNING) << "GetObjectManagerProfileInfo handler took " << interval << " ms.";
+  }
+}
+
 void NodeManager::ClientAdded(const ClientTableDataT &client_data) {
   const ClientID client_id = ClientID::from_binary(client_data.client_id);
 

src/ray/raylet/node_manager.h

@@ -104,8 +104,15 @@ class NodeManager {
   /// \param client_data Data associated with the removed client.
   /// \return Void.
   void ClientRemoved(const ClientTableDataT &client_data);
+
   /// Send heartbeats to the GCS.
   void Heartbeat();
+
+  /// Get profiling information from the object manager and push it to the GCS.
+  ///
+  /// \return Void.
+  void GetObjectManagerProfileInfo();
+
   /// Handler for a heartbeat notification from the GCS.
   ///
   /// \param client The GCS client.
@@ -339,6 +346,9 @@ class NodeManager {
   boost::asio::steady_timer heartbeat_timer_;
   /// The period used for the heartbeat timer.
   std::chrono::milliseconds heartbeat_period_;
+  /// The timer used to get profiling information from the object manager and
+  /// push it to the GCS.
+  boost::asio::steady_timer object_manager_profile_timer_;
   /// The time that the last heartbeat was sent at. Used to make sure we are
   /// keeping up with heartbeats.
   uint64_t last_heartbeat_at_ms_;

src/ray/util/util.h

@@ -29,6 +29,18 @@ inline int64_t current_sys_time_ms() {
   return ms_since_epoch.count();
 }
 
+inline int64_t current_sys_time_us() {
+  std::chrono::microseconds mu_since_epoch =
+      std::chrono::duration_cast<std::chrono::microseconds>(
+          std::chrono::system_clock::now().time_since_epoch());
+  return mu_since_epoch.count();
+}
+
+inline double current_sys_time_seconds() {
+  int64_t microseconds_in_seconds = 1000000;
+  return static_cast<double>(current_sys_time_us()) / microseconds_in_seconds;
+}
+
 inline ray::Status boost_to_ray_status(const boost::system::error_code &error) {
   switch (error.value()) {
   case boost::system::errc::success:

test/runtest.py

@@ -2,6 +2,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import json
 import os
 import re
 import setproctitle
@@ -17,6 +18,7 @@ import pytest
 
 import ray
 import ray.ray_constants as ray_constants
+import ray.test.cluster_utils
 import ray.test.test_utils
 
 
@@ -1037,6 +1039,58 @@ def test_profiling_api(shutdown_only):
             break
 
 
+@pytest.fixture()
+def ray_start_cluster():
+    cluster = ray.test.cluster_utils.Cluster()
+    yield cluster
+
+    # The code after the yield will run as teardown code.
+    ray.shutdown()
+    cluster.shutdown()
+
+
+def test_object_transfer_dump(ray_start_cluster):
+    cluster = ray_start_cluster
+
+    num_nodes = 3
+    for i in range(num_nodes):
+        cluster.add_node(resources={str(i): 1}, object_store_memory=10**9)
+
+    ray.init(redis_address=cluster.redis_address)
+
+    @ray.remote
+    def f(x):
+        return
+
+    # These objects will live on different nodes.
+    object_ids = [
+        f._submit(args=[1], resources={str(i): 1}) for i in range(num_nodes)
+    ]
+
+    # Broadcast each object from each machine to each other machine.
+    for object_id in object_ids:
+        ray.get([
+            f._submit(args=[object_id], resources={str(i): 1})
+            for i in range(num_nodes)
+        ])
+
+    # The profiling information only flushes once every second.
+    time.sleep(1.1)
+
+    transfer_dump = ray.global_state.chrome_tracing_object_transfer_dump()
+    # Make sure the transfer dump can be serialized with JSON.
+    json.loads(json.dumps(transfer_dump))
+    assert len(transfer_dump) >= num_nodes**2
+    assert len({
+        event["pid"]
+        for event in transfer_dump if event["name"] == "transfer_receive"
+    }) == num_nodes
+    assert len({
+        event["pid"]
+        for event in transfer_dump if event["name"] == "transfer_send"
+    }) == num_nodes
+
+
 def test_identical_function_names(shutdown_only):
     # Define a bunch of remote functions and make sure that we don't
     # accidentally call an older version.