simplify comments

Signed-off-by: sampan <sampan@anyscale.com>

Author: sampan

python/ray/tests/test_gcs_pubsub.py

@@ -258,15 +258,8 @@ def test_pubsub_subscriptions_bounded_for_regular_cluster(ray_start_cluster):
     cluster = ray_start_cluster
     cluster.wait_for_nodes()
 
-    # Spin up several workers. Each task blocks until all of them are running,
-    # so Ray is forced to start a distinct worker process per task instead of
-    # reusing a couple of them. This is what makes the assertions below
-    # meaningful: they must hold with many workers alive, not just a few.
-    #
-    # The barrier is deliberately a shared directory rather than a SignalActor:
-    # a worker holding an actor handle subscribes to that actor's key on
-    # GCS_ACTOR_CHANNEL, which would make the actor channel counts asserted
-    # below scale with num_workers and mask exactly what this test guards.
+    # Spin up several workers. and block them so that ray is forced to create new workers for each task
+    # we avoid using a signal actor for this because it would create a subscription for each worker.
     barrier_dir = tempfile.mkdtemp()
 
     @ray.remote(num_cpus=0.5)
@@ -300,12 +293,13 @@ def f(self):
     session_dir = ray._private.worker.global_worker.node.address_info["session_dir"]
     gcs_log_path = os.path.join(session_dir, "logs", "gcs_server.out")
 
-    # Total long-polling connections into the GCS publisher. Measured with
-    # num_nodes=3: the 3 raylets, the driver, the generator actor's worker, and
-    # 2 dashboard/agent subscribers. The exact value matters less than the
+    # 3 raylets (num_nodes=3) + 1 driver + 1 generator actor's worker + 2 from the
+    # dashboard head(its node-info and actor subscribers each mint their own
+    # subscriber id (gcs_pubsub.py _SubscriberBase.__init__), so one process
+    # holds two long-poll connections). The exact value matters less than the
     # invariant it pins: it must not grow with num_workers (verified unchanged
     # at num_workers=6 and num_workers=12).
-    expected_long_polling_subscribers = 7
+    expected_long_polling_subscribers = num_nodes + 4
 
     def check():
         stats = _gcs_publisher_stats(gcs_log_path)