update by comment

paddle/fluid/operators/listen_and_serv_op.cc

@@ -308,7 +308,10 @@ void ListenAndServOp::RunImpl(const framework::Scope &scope,
   rpc_service_->WaitServerReady();
 
   // Write to a file of server selected port for python use.
-  SavePort();
+  std::string file_path =
+    string::Sprintf("/tmp/paddle.%d.selected_port",
+                    static_cast<int>(::getpid()));
+  SavePort(file_path);
   if (sync_mode) {
     RunSyncLoop(&executor, program, &recv_scope, prefetch_block);
   } else {

paddle/fluid/operators/send_recv_op_test.cc

@@ -198,8 +198,11 @@ TEST(SendRecvOp, CPUSparse) {
   std::thread server_thread(StartServerNet, true, &initialized);
   while (!initialized) {
   }
-  static_cast<paddle::operators::ListenAndServOp *>(listen_and_serv_op.get())
-      ->WaitServerReady();
+  auto *listen_and_serv_op_ptr =
+      static_cast<paddle::operators::ListenAndServOp *>(
+          listen_and_serv_op.get());
+  ASSERT_TRUE(listen_and_serv_op_ptr != nullptr);
+  listen_and_serv_op_ptr->WaitServerReady();
 
   // local net
   f::Scope scope;
@@ -208,10 +211,6 @@ TEST(SendRecvOp, CPUSparse) {
   InitSelectedRowsInScope(place, &scope);
   scope.Var("RPC_CLIENT_VAR");
   f::AttributeMap attrs;
-  auto *listen_and_serv_op_ptr =
-      static_cast<paddle::operators::ListenAndServOp *>(
-          listen_and_serv_op.get());
-  ASSERT_TRUE(listen_and_serv_op_ptr != nullptr);
   selected_port = listen_and_serv_op_ptr->GetSelectedPort();
   std::string endpoint = paddle::string::Sprintf("127.0.0.1:%d", selected_port);
   attrs.insert({"endpoints", std::vector<std::string>({endpoint})});

python/paddle/fluid/tests/unittests/test_dist_train.py

@@ -34,7 +34,7 @@ class TestSendOp(unittest.TestCase):
         p.start()
 
         time.sleep(10)
-        with open("/tmp/paddle.selected_port", "r") as fn:
+        with open("/tmp/paddle.%d.selected_port" % p.pid, "r") as fn:
             selected_port = int(fn.readlines()[0])
         self.init_client(place, selected_port)