Issue/#1015 Fix pop timer rate calculation

server/matchmaker/matchmaker_queue.py

@@ -108,6 +108,15 @@ def initialize(self):
     def num_players(self) -> int:
         return sum(len(search.players) for search in self._queue.keys())
 
+    @property
+    def num_new_queued_players(self) -> int:
+        """ Get the number of players who have joined the queue and not yet had a failed matching attempt in the last pop.
+
+        Returns:
+            int: Number of players who have joined the queue since last matching attempt.
+        """
+        return sum(len(search.players) for search in self._queue.keys() if search.failed_matching_attempts == 0)
+
     async def queue_pop_timer(self) -> None:
         """ Periodically tries to match all Searches in the queue. The amount
         of time until next queue 'pop' is determined by the number of players

server/matchmaker/pop_timer.py

@@ -56,9 +56,12 @@ async def next_pop(self):
         num_players = self.queue.num_players
         metrics.matchmaker_players.labels(self.queue.name).set(num_players)
 
+        num_new_players = self.queue.num_new_queued_players
+        metrics.matchmaker_new_players.labels(self.queue.name).set(num_new_players)
+
         self._last_queue_pop = time()
         self.next_queue_pop = self._last_queue_pop + self.time_until_next_pop(
-            num_players, time_remaining
+            num_new_players, time_remaining
         )
 
     def time_until_next_pop(self, num_queued: int, time_queued: float) -> float:
@@ -82,8 +85,9 @@ def time_until_next_pop(self, num_queued: int, time_queued: float) -> float:
 
         players_per_match = self.queue.team_size * 2
         desired_players = config.QUEUE_POP_DESIRED_MATCHES * players_per_match
-        # Obtained by solving $ NUM_PLAYERS = rate * time $ for time.
-        next_pop_time = desired_players * total_times / total_players
+        player_addition_rate = total_players / total_times
+        # Obtained by solving $ desired_players = player_addition_rate * time $ for time.
+        next_pop_time = desired_players / player_addition_rate
         if next_pop_time > config.QUEUE_POP_TIME_MAX:
             self._logger.info(
                 "Required time (%.2fs) for %s is larger than max pop time (%ds). "

server/metrics.py

@@ -67,6 +67,10 @@ class MatchLaunch:
     "server_matchmaker_queue_players", "Players in the queue at pop time", ["queue"]
 )
 
+matchmaker_new_players = Gauge(
+    "server_matchmaker_queue_new_players", "Number of newly added players to the queue at pop time", ["queue"]
+)
+
 matchmaker_queue_pop = Gauge(
     "server_matchmaker_queue_pop_timer_seconds",
     "Queue pop timer duration in seconds",

tests/unit_tests/test_pop_timer.py

@@ -43,3 +43,16 @@ def test_queue_pop_time_moving_average_size(queue_factory):
 
     # The rate should be extremely low, meaning the pop time should be high
     assert t1.time_until_next_pop(0, 100) == config.QUEUE_POP_TIME_MAX
+
+
+def test_queue_pop_time_moving_average_size_stability(queue_factory):
+    # Test perfect number of players joining has a stable pop time
+    team_size = 2
+    desired_players = team_size * config.QUEUE_POP_DESIRED_MATCHES
+    t1 = PopTimer(queue_factory(team_size=2))
+    initial_time_to_pop = (config.QUEUE_POP_TIME_MAX + config.QUEUE_POP_TIME_MIN) / 2  # Arbitrary time between min and max
+    next_time_to_pop = initial_time_to_pop
+    for _ in range(100):
+        next_time_to_pop = t1.time_until_next_pop(desired_players, next_time_to_pop)
+
+    assert t1.time_until_next_pop(desired_players, next_time_to_pop) == next_time_to_pop  # Perfect size should not change the next time