diff --git a/paddle/framework/executor.cc b/paddle/framework/executor.cc
index 51ddb7e58e2505b7df48a9e365854371fcc0a12c..ee0df039acd446bc7952186d0870688f9b2dfb46 100644
--- a/paddle/framework/executor.cc
+++ b/paddle/framework/executor.cc
@@ -74,16 +74,6 @@ void Executor::Run(const ProgramDesc& pdesc, Scope* scope) {
   for (auto& device_context : device_contexts_) {
     device_context->Wait();
   }
-  // // print tensor value
-  // for (auto& var : block.vars()) {
-  //   std::cout << var.name() << std::endl;
-  //   auto v = scope->FindVar(var.name());
-  //   const LoDTensor& t = v->Get<LoDTensor>();
-  //   for (int i = 0; i < t.numel(); ++i) {
-  //     std::cout << t.data<float>()[i] << " ";
-  //   }
-  //   std::cout << std::endl;
-  // }
 }
 
 }  // namespace framework
diff --git a/paddle/framework/executor_test.cc b/paddle/framework/executor_test.cc
index d3ea18d1546059d5e3e601cde5823c7d89e6a226..5e327cc893e3a393b758a06f6a6f33173d0e86db 100644
--- a/paddle/framework/executor_test.cc
+++ b/paddle/framework/executor_test.cc
@@ -130,6 +130,7 @@ std::once_flag set_variable_flag;
 template <typename T>
 void set_feed_variable(const std::vector<std::vector<T>>& inputs) {
   typedef std::vector<paddle::framework::Tensor> FeedInputs;
+  // Tensors in feed value variable will only be in CPUPlace
   Variable* g_feed_value = GetScope()->FindVar("feed_value");
   FeedInputs& feed_inputs = *(g_feed_value->GetMutable<FeedInputs>());
   auto size = inputs.size();
@@ -144,6 +145,7 @@ void set_feed_variable(const std::vector<std::vector<T>>& inputs) {
 template <typename T>
 std::vector<std::vector<T>> get_fetch_variable() {
   typedef std::vector<paddle::framework::Tensor> FetchOutputs;
+  // Tensors in fetch value variable will only be in CPUPlace
   Variable* g_fetch_value = GetScope()->FindVar("fetch_value");
   FetchOutputs& fetch_outputs = *(g_fetch_value->GetMutable<FetchOutputs>());
 
diff --git a/paddle/framework/scope.cc b/paddle/framework/scope.cc
index 2c416570cf62c8a4375293062cfc1e47f1011024..b6a9d7fbc29c58fc986b910f9b510f25e2e42ad9 100644
--- a/paddle/framework/scope.cc
+++ b/paddle/framework/scope.cc
@@ -66,15 +66,10 @@ void Scope::DropKids() {
 
 std::once_flag feed_variable_flag;
 
-template <typename T, typename... Args>
-std::unique_ptr<T> make_unique(Args&&... args) {
-  return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
-}
-
 framework::Scope* GetScope() {
-  static std::unique_ptr<framework::Scope> g_scope =
-      make_unique<framework::Scope>();
+  static std::unique_ptr<framework::Scope> g_scope{nullptr};
   std::call_once(feed_variable_flag, [&]() {
+    g_scope.reset(new framework::Scope());
     g_scope->NewVar("feed_value");
     g_scope->NewVar("fetch_value");
   });
diff --git a/paddle/operators/feed_op.cc b/paddle/operators/feed_op.cc
index d40db3ff2ed8799504a9d6e816d73adb63abf2e6..f2c498e2e2ccb26e29e9d1364ec0aca4fbe105f7 100644
--- a/paddle/operators/feed_op.cc
+++ b/paddle/operators/feed_op.cc
@@ -33,7 +33,7 @@ class FeedOp : public framework::OperatorWithKernel {
 
     auto in_dim = tensors[col].dims();
     ctx->SetOutputDim("Out", in_dim);
-    // TODO(qijun) need to handle LodTensor later
+    // TODO(qijun): need to handle LodTensor later
   }
 
   framework::DataType IndicateDataType(
diff --git a/paddle/operators/fetch_op.cc b/paddle/operators/fetch_op.cc
index a885deacc84379389302d1420303ca8b608c9455..f6882cbd03462942f67b2ec8e32256d35991b6b2 100644
--- a/paddle/operators/fetch_op.cc
+++ b/paddle/operators/fetch_op.cc
@@ -39,7 +39,7 @@ class FetchOp : public framework::OperatorWithKernel {
     tmp.Resize(input_dim);
     (*tensors)[col].Resize(input_dim);
 
-    // TODO(qijun) need to handle LodTensor later
+    // TODO(qijun): need to handle LodTensor later
   }
 
   framework::DataType IndicateDataType(