diff --git a/visualdl/backend/logic/pybind.cc b/visualdl/backend/logic/pybind.cc
index 9b7f67727..4b114a533 100644
--- a/visualdl/backend/logic/pybind.cc
+++ b/visualdl/backend/logic/pybind.cc
@@ -62,7 +62,7 @@ PYBIND11_PLUGIN(core) {
         &vs::start_write_service,
         "global information-maintainer object.");
   m.def("im", &vs::im);
-  m.def("stop_threads", &vs::StopThreads);
+  m.def("stop_threads", &vs::stop_threads);
 
 // interfaces for components
 #define ADD_SCALAR_TYPED_INTERFACE(T, name__)                             \
diff --git a/visualdl/backend/logic/sdk.cc b/visualdl/backend/logic/sdk.cc
index 4ce6362fb..b5bebe56d 100644
--- a/visualdl/backend/logic/sdk.cc
+++ b/visualdl/backend/logic/sdk.cc
@@ -60,8 +60,6 @@ std::string TabletHelper::human_readable_buffer() const {
   return buffer;
 }
 
-void ImHelper::PersistToDisk() const { IM::Global().PersistToDisk(); }
-
 // implementations for components
 namespace components {
 
diff --git a/visualdl/backend/logic/sdk.h b/visualdl/backend/logic/sdk.h
index e97d4f85d..9948ab709 100644
--- a/visualdl/backend/logic/sdk.h
+++ b/visualdl/backend/logic/sdk.h
@@ -96,14 +96,69 @@ class ImHelper {
 public:
   ImHelper() {}
 
-  /*
-   * mode:
-   * 0: read
-   * 1: write
-   * 2: none
-   */
+  StorageHelper storage() {
+    return StorageHelper(IM::Global().storage().mutable_data());
+  }
+  TabletHelper tablet(const std::string &tag) {
+    return TabletHelper(IM::Global().storage().tablet(tag));
+  }
+  TabletHelper AddTablet(const std::string &tag, int num_samples) {
+    return TabletHelper(IM::Global().AddTablet(tag, num_samples));
+  }
+  void ClearTablets() {
+    IM::Global().storage().mutable_data()->clear_tablets();
+  }
+
+  void PersistToDisk() const { IM::Global().PersistToDisk(); }
+};
+
+namespace components {
+
+/*
+ * Read and write support for Scalar component.
+ */
+template <typename T>
+class ScalarHelper {
+public:
+  ScalarHelper(storage::Tablet *tablet) : data_(tablet) {}
+
+  void SetCaptions(const std::vector<std::string> &captions);
+
+  void AddRecord(int id, const std::vector<T> &values);
+
+  std::vector<std::vector<T>> GetRecords() const;
+
+  std::vector<int> GetIds() const;
+
+  std::vector<int> GetTimestamps() const;
+
+  std::vector<std::string> GetCaptions() const;
+
+  size_t GetSize() const { return data_->records_size(); }
+
+private:
+  storage::Tablet *data_;
+};
+
+}  // namespace components
+
+static ImHelper &im() {
+  static ImHelper im;
+  return im;
+}
+
+static void start_read_service(const std::string &dir) {
+  IM::Global().SetPersistDest(dir);
+  IM::Global().MaintainRead();
+}
+
+static void start_write_service(const std::string &dir) {
+  IM::Global().SetPersistDest(dir);
+  IM::Global().MaintainWrite();
 }
 
+static void stop_threads() { cc::PeriodExector::Global().Quit(); }
+
 }  // namespace visualdl
 
 #endif  // VISUALDL_BACKEND_LOGIC_SDK_H
diff --git a/visualdl/backend/storage/CMakeLists.txt b/visualdl/backend/storage/CMakeLists.txt
index 2885b8452..090f162ec 100644
--- a/visualdl/backend/storage/CMakeLists.txt
+++ b/visualdl/backend/storage/CMakeLists.txt
@@ -4,5 +4,5 @@ add_library(storage_proto ${PROTO_SRCS})
 add_dependencies(storage_proto protobuf)
 
 ## add storage as target
-add_library(storage storage.cc ${PROTO_SRCS} ${PROTO_HDRS})
+add_library(storage storage.cc storage.h ${PROTO_SRCS} ${PROTO_HDRS})
 add_dependencies(storage storage_proto)
diff --git a/visualdl/backend/utils/concurrency.h b/visualdl/backend/utils/concurrency.h
index a3d46a9a8..45c8f88cc 100644
--- a/visualdl/backend/utils/concurrency.h
+++ b/visualdl/backend/utils/concurrency.h
@@ -30,12 +30,27 @@ struct PeriodExector {
   void Start() { quit = false; }
 
   void operator()(task_t&& task, int msec) {
+    const int interval = 500;
+
     auto task_wrapper = [=] {
       while (!quit) {
         if (!task()) break;
-        std::this_thread::sleep_for(std::chrono::milliseconds(msec));
+        // if the program is terminated, quit while as soon as possible.
+        // this is just trick, but should works.
+        if (msec > 1000) {
+          int i;
+          for (i = 0; i < msec / interval; i++) {
+            if (quit) break;
+            std::this_thread::sleep_for(std::chrono::milliseconds(interval));
+          }
+          std::this_thread::sleep_for(
+              std::chrono::milliseconds(msec - i * interval));
+          if (quit) break;
+        } else {
+          std::this_thread::sleep_for(std::chrono::milliseconds(msec));
+        }
       }
-      LOG(INFO) << "quit job";
+      LOG(INFO) << "quit concurrent job";
     };
     threads_.emplace_back(std::thread(std::move(task_wrapper)));
     msec_ = msec;