Fix hang of hybrid parallel in new_group (#33141)

* fix hang of hybrid parallel

* fix new_group for hang problem

python/paddle/distributed/collective.py

@@ -239,31 +239,37 @@ def new_group(ranks=None, backend=None):
     if global_rank not in ranks:
         gp = Group(-1, -1, ring_id, ranks)
         _group_map[ring_id] = gp
-        return gp
-
+    else:
         ranks = sorted(ranks)
         group_rank = ranks.index(global_rank)
         group_size = len(ranks)
         gp = Group(group_rank, group_size, ring_id, ranks)
         _group_map[ring_id] = gp
 
-    if group_size < 2:
-        return gp
-
+        if group_size >= 2:
             strategy = core.ParallelStrategy()
             strategy.nranks = group_size
             strategy.local_rank = group_rank
-    strategy.trainer_endpoints = [genv.trainer_endpoints[i] for i in ranks]
+            strategy.trainer_endpoints = [
+                genv.trainer_endpoints[i] for i in ranks
+            ]
             strategy.current_endpoint = genv.current_endpoint
             strategy.nrings = 1
 
             if core.is_compiled_with_cuda():
                 place = core.CUDAPlace(genv.device_id)
-        core.NCCLParallelContext(strategy, place).init_with_ring_id(ring_id)
+                core.NCCLParallelContext(strategy,
+                                         place).init_with_ring_id(ring_id)
             else:
                 assert False, ("no cuda device found")
-    # need to barrier to construct group
-    barrier(gp)
+        else:
+            return gp
+
+    # TODO(shenliang03): This is a temporary solution to solve the problem of 
+    # hang caused by cross-creation of new_group
+    tmp = fill_constant([0], dtype="int32", value="1")
+    paddle.distributed.all_reduce(tmp, use_calc_stream=True)
+    paddle.distributed.wait(tmp)
     return gp