[KVStore] Fix bug in barrier. (#1904)

* update

* update

* fix lint

* update

* update

python/dgl/distributed/kvstore.py

@@ -549,8 +549,15 @@ class RegisterRoleRequest(rpc.Request):
             role[self.role] = set()
             kv_store.barrier_count[self.role] = 0
         role[self.role].add(self.client_id)
-        res = RegisterRoleResponse(ROLE_MSG)
-        return res
+        total_count = 0
+        for key in role:
+            total_count += len(role[key])
+        if total_count == kv_store.num_clients:
+            res_list = []
+            for target_id in range(kv_store.num_clients):
+                res_list.append((target_id, RegisterRoleResponse(ROLE_MSG)))
+            return res_list
+        return None
 
 ############################ KVServer ###############################
 

tests/distributed/test_new_kvstore.py

@@ -151,7 +151,6 @@ def start_client(num_clients):
     dgl.distributed.connect_to_server(ip_config='kv_ip_config.txt')
     # Init kvclient
     kvclient = dgl.distributed.KVClient(ip_config='kv_ip_config.txt')
-    time.sleep(2)
     assert dgl.distributed.get_num_client() == num_clients
     kvclient.init_data(name='data_1', 
                        shape=F.shape(data_1), 
@@ -286,7 +285,6 @@ def start_client_mul_role(i, num_clients):
         kvclient = dgl.distributed.KVClient(ip_config='kv_ip_mul_config.txt', role='trainer')
     else:
         kvclient = dgl.distributed.KVClient(ip_config='kv_ip_mul_config.txt', role='sampler')
-    time.sleep(2)
     if i == 2: # block one trainer
         time.sleep(5)
     kvclient.barrier()