From 2bbfc5da8dd863cb9b3ea5630a8dd1338a54e6ec Mon Sep 17 00:00:00 2001
From: Robert Nishihara <robertnishihara@gmail.com>
Date: Fri, 28 Apr 2017 17:36:43 -0700
Subject: [PATCH] Dispatch actor tasks when actor connects. (#495)

---
 .../local_scheduler_algorithm.cc              | 107 +++++++++---------
 1 file changed, 54 insertions(+), 53 deletions(-)

diff --git a/src/local_scheduler/local_scheduler_algorithm.cc b/src/local_scheduler/local_scheduler_algorithm.cc
index 55a068b70..874bef5c7 100644
--- a/src/local_scheduler/local_scheduler_algorithm.cc
+++ b/src/local_scheduler/local_scheduler_algorithm.cc
@@ -282,6 +282,59 @@ void remove_actor(SchedulingAlgorithmState *algorithm_state, ActorID actor_id) {
   algorithm_state->local_actor_infos.erase(actor_id);
 }
 
+/**
+ * Dispatch a task to an actor if possible.
+ *
+ * @param state The state of the local scheduler.
+ * @param algorithm_state The state of the scheduling algorithm.
+ * @param actor_id The ID of the actor corresponding to the worker.
+ * @return True if a task was dispatched to the actor and false otherwise.
+ */
+bool dispatch_actor_task(LocalSchedulerState *state,
+                         SchedulingAlgorithmState *algorithm_state,
+                         ActorID actor_id) {
+  /* Make sure this worker actually is an actor. */
+  CHECK(!ActorID_equal(actor_id, NIL_ACTOR_ID));
+  /* Make sure this actor belongs to this local scheduler. */
+  CHECK(state->actor_mapping.count(actor_id) == 1);
+  CHECK(DBClientID_equal(state->actor_mapping[actor_id].local_scheduler_id,
+                         get_db_client_id(state->db)))
+
+  /* Get the local actor entry for this actor. */
+  CHECK(algorithm_state->local_actor_infos.count(actor_id) != 0);
+  LocalActorInfo &entry =
+      algorithm_state->local_actor_infos.find(actor_id)->second;
+
+  if (entry.task_queue->empty()) {
+    /* There are no queued tasks for this actor, so we cannot dispatch a task to
+     * the actor. */
+    return false;
+  }
+  TaskQueueEntry first_task = entry.task_queue->front();
+  int64_t next_task_counter = TaskSpec_actor_counter(first_task.spec);
+  if (next_task_counter != entry.task_counter) {
+    /* We cannot execute the next task on this actor without violating the
+     * in-order execution guarantee for actor tasks. */
+    CHECK(next_task_counter > entry.task_counter);
+    return false;
+  }
+  /* If the worker is not available, we cannot assign a task to it. */
+  if (!entry.worker_available) {
+    return false;
+  }
+  /* Assign the first task in the task queue to the worker and mark the worker
+   * as unavailable. */
+  entry.task_counter += 1;
+  assign_task_to_worker(state, first_task.spec, first_task.task_spec_size,
+                        entry.worker);
+  entry.worker_available = false;
+  /* Free the task queue entry. */
+  TaskQueueEntry_free(&first_task);
+  /* Remove the task from the actor's task queue. */
+  entry.task_queue->pop_front();
+  return true;
+}
+
 void handle_actor_worker_connect(LocalSchedulerState *state,
                                  SchedulingAlgorithmState *algorithm_state,
                                  ActorID actor_id,
@@ -294,6 +347,7 @@ void handle_actor_worker_connect(LocalSchedulerState *state,
      * filled out, so fill out the correct worker field now. */
     algorithm_state->local_actor_infos[actor_id].worker = worker;
   }
+  dispatch_actor_task(state, algorithm_state, actor_id);
 }
 
 void handle_actor_worker_disconnect(LocalSchedulerState *state,
@@ -381,59 +435,6 @@ void add_task_to_actor_queue(LocalSchedulerState *state,
   }
 }
 
-/**
- * Dispatch a task to an actor if possible.
- *
- * @param state The state of the local scheduler.
- * @param algorithm_state The state of the scheduling algorithm.
- * @param actor_id The ID of the actor corresponding to the worker.
- * @return True if a task was dispatched to the actor and false otherwise.
- */
-bool dispatch_actor_task(LocalSchedulerState *state,
-                         SchedulingAlgorithmState *algorithm_state,
-                         ActorID actor_id) {
-  /* Make sure this worker actually is an actor. */
-  CHECK(!ActorID_equal(actor_id, NIL_ACTOR_ID));
-  /* Make sure this actor belongs to this local scheduler. */
-  CHECK(state->actor_mapping.count(actor_id) == 1);
-  CHECK(DBClientID_equal(state->actor_mapping[actor_id].local_scheduler_id,
-                         get_db_client_id(state->db)))
-
-  /* Get the local actor entry for this actor. */
-  CHECK(algorithm_state->local_actor_infos.count(actor_id) != 0);
-  LocalActorInfo &entry =
-      algorithm_state->local_actor_infos.find(actor_id)->second;
-
-  if (entry.task_queue->empty()) {
-    /* There are no queued tasks for this actor, so we cannot dispatch a task to
-     * the actor. */
-    return false;
-  }
-  TaskQueueEntry first_task = entry.task_queue->front();
-  int64_t next_task_counter = TaskSpec_actor_counter(first_task.spec);
-  if (next_task_counter != entry.task_counter) {
-    /* We cannot execute the next task on this actor without violating the
-     * in-order execution guarantee for actor tasks. */
-    CHECK(next_task_counter > entry.task_counter);
-    return false;
-  }
-  /* If the worker is not available, we cannot assign a task to it. */
-  if (!entry.worker_available) {
-    return false;
-  }
-  /* Assign the first task in the task queue to the worker and mark the worker
-   * as unavailable. */
-  entry.task_counter += 1;
-  assign_task_to_worker(state, first_task.spec, first_task.task_spec_size,
-                        entry.worker);
-  entry.worker_available = false;
-  /* Free the task queue entry. */
-  TaskQueueEntry_free(&first_task);
-  /* Remove the task from the actor's task queue. */
-  entry.task_queue->pop_front();
-  return true;
-}
-
 /**
  * Fetch a queued task's missing object dependency. The fetch request will be
  * retried every LOCAL_SCHEDULER_FETCH_TIMEOUT_MILLISECONDS until the object is