[fix][RL] Remove the incorrect barrier in init_weights_update_group (#5914)

python/sglang/srt/model_executor/model_runner.py

@@ -631,7 +631,6 @@ class ModelRunner:
                 rank=rank,
                 group_name=group_name,
             )
-            dist.barrier(group=self._model_update_group, device_ids=[rank])
             return True, "Succeeded to initialize custom process group."
         except Exception as e:
             message = f"Failed to initialize custom process group: {e}."

test/srt/test_update_weights_from_distributed.py

@@ -162,7 +162,6 @@ def init_process_hf(
         rank=rank,
         group_name="test_parameter_update_group",
     )
-    dist.barrier(group=group, device_ids=[rank])
     torch.cuda.synchronize()
     time_begin_broadcast = time.perf_counter()
 
@@ -223,8 +222,8 @@ def init_process_sgl(
         if rank == 1:
             url = DEFAULT_URL_FOR_TEST
         else:
-            host, port = DEFAULT_URL_FOR_TEST.split(":")
-            url = ":".join(host, str(int(port) + 10000))
+            host, _, port = DEFAULT_URL_FOR_TEST.rpartition(":")
+            url = ":".join([host, str(int(port) + 10000)])
 
         print(f"[sgl] rank {rank} init server on url: {url}")
         process = popen_launch_server(