diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9ab453b7520134448e4e418751541638ea2d06dd..b4e6b67b22386444418d8f17d08311de87096c10 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,5 +31,9 @@ add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/visualdl/backend/logic)
 add_executable(vl_test
         ${PROJECT_SOURCE_DIR}/visualdl/backend/test.cc
         ${PROJECT_SOURCE_DIR}/visualdl/backend/storage/storage_test.cc
-        ${PROJECT_SOURCE_DIR}/visualdl/backend/logic/im_test.cc)
+        ${PROJECT_SOURCE_DIR}/visualdl/backend/utils/test_concurrency.cc
+        ${PROJECT_SOURCE_DIR}/visualdl/backend/logic/im_test.cc
+        ${PROJECT_SOURCE_DIR}/visualdl/backend/utils/concurrency.h
+        ${PROJECT_SOURCE_DIR}/visualdl/backend/utils/filesystem.h
+        )
 target_link_libraries(vl_test storage im gtest glog protobuf gflags pthread)
diff --git a/visualdl/backend/logic/im.cc b/visualdl/backend/logic/im.cc
index e33ac2768bd5325051f9a71ec6be880389c06dcd..305fb42c73cf4c6992a7d7fbd71ccbb00f7f7a5d 100644
--- a/visualdl/backend/logic/im.cc
+++ b/visualdl/backend/logic/im.cc
@@ -25,20 +25,39 @@ int ReserviorSample(int num_samples, int num_records) {
   return -1;
 }
 
-void InformationMaintainer::SetPersistDest(const std::string &path) {
+IM::IM(StorageBase::Type type, StorageBase::Mode mode) {
+  switch (type) {
+    case StorageBase::Type::kMemory: {
+      storage_.reset(new MemoryStorage);
+    } break;
+    default:
+      CHECK(false) << "Unsupported storage kind " << type;
+  }
+
+  switch (mode) {
+    case StorageBase::Mode::kRead:
+      dynamic_cast<MemoryStorage *>(storage_.get())->StartReadService();
+      break;
+    case StorageBase::Mode::kWrite:
+      dynamic_cast<MemoryStorage *>(storage_.get())->StartWriteSerice();
+      break;
+    default:
+      break;
+  }
+}
+
+void IM::SetPersistDest(const std::string &path) {
   CHECK(storage_->mutable_data()->dir().empty())
       << "duplicate set storage's path";
   storage_->mutable_data()->set_dir(path);
 }
 
-storage::Tablet *InformationMaintainer::AddTablet(const std::string &tag,
-                                                  int num_samples) {
+storage::Tablet *IM::AddTablet(const std::string &tag, int num_samples) {
   auto tablet = storage_->NewTablet(tag, num_samples);
   return tablet;
 }
 
-void InformationMaintainer::AddRecord(const std::string &tag,
-                                      const storage::Record &data) {
+void IM::AddRecord(const std::string &tag, const storage::Record &data) {
   auto *tablet = storage_->tablet(tag);
   CHECK(tablet) << "no tablet called " << tag;
 
@@ -65,14 +84,14 @@ void InformationMaintainer::AddRecord(const std::string &tag,
   tablet->set_total_records(num_records + 1);
 }
 
-void InformationMaintainer::Clear() {
+void IM::Clear() {
   auto *data = storage().mutable_data();
   data->clear_tablets();
   data->clear_dir();
   data->clear_timestamp();
 }
 
-void InformationMaintainer::PersistToDisk() {
+void IM::PersistToDisk() {
   CHECK(!storage_->data().dir().empty()) << "path of storage should be set";
   // TODO make dir first
   // MakeDir(storage_.data().dir());
diff --git a/visualdl/backend/logic/im.h b/visualdl/backend/logic/im.h
index d96aa4d55feb3947708d6dd26a89a8da915341fd..de884b0a890a97025e90a90342909e9b33a6ba18 100644
--- a/visualdl/backend/logic/im.h
+++ b/visualdl/backend/logic/im.h
@@ -2,6 +2,7 @@
 #define VISUALDL_BACKEND_LOGIC_IM_H
 
 #include <glog/logging.h>
+#include <visualdl/backend/utils/concurrency.h>
 #include <memory>
 #include <string>
 
@@ -10,24 +11,38 @@
 namespace visualdl {
 
 /*
- * Maintain the Storage singleton in memory, pre-compute some the statical
- * information to help visualizaton.
+ * IM(Information Maintainer) maintain the Storage singleton in memory,
+ * pre-compute some the statistical information to help visualizaton.
+ *
+ * There should be two processes and each have an IM, one is the web server
+ * which hold one IM to read the storage, the other is the SDK(python or C++),
+ * it will get an IM to write latest changes to storage.
+ *
+ * An IM have an underlying Storage object, which might be a memory based
+ * storage or a disk based one, both has the same interfaces those defined by
+ * class StorageBase.
+ *
+ * The SDK's IM will maintain the changes and periodically write to disk, and
+ * the web server's IM will periodically read latest storage from disk.
  */
-class InformationMaintainer final {
+class IM final {
 public:
-  InformationMaintainer(StorageBase::Type type = StorageBase::Type::kMemory) {
-    switch (type) {
-      case StorageBase::Type::kMemory:
-        storage_.reset(new MemoryStorage);
-        break;
-      default:
-        CHECK(false) << "Unsupported storage kind " << type;
-    }
+  IM() { storage_.reset(new MemoryStorage); }
+  IM(StorageBase::Type type, StorageBase::Mode mode);
+  ~IM() { cc::PeriodExector::Global().Quit(); }
+
+  static IM &Global() {
+    static IM x;
+    return x;
+  }
+
+  void MaintainRead() {
+    LOG(INFO) << "start maintain read";
+    dynamic_cast<MemoryStorage *>(storage_.get())->StartReadService();
   }
 
-  static InformationMaintainer &Global() {
-    static InformationMaintainer *x = new InformationMaintainer();
-    return *x;
+  void MaintainWrite() {
+    dynamic_cast<MemoryStorage *>(storage_.get())->StartWriteSerice();
   }
 
   /*
diff --git a/visualdl/backend/logic/im_test.cc b/visualdl/backend/logic/im_test.cc
index 183853e501143ffd33714b69c1c02162bf1d6f57..c387565477ee9df0ae8d2872ae6416f79e08ca7e 100644
--- a/visualdl/backend/logic/im_test.cc
+++ b/visualdl/backend/logic/im_test.cc
@@ -8,7 +8,7 @@ class ImTester : public ::testing::Test {
 protected:
   void SetUp() override {}
 
-  InformationMaintainer &im = InformationMaintainer::Global();
+  IM &im = IM::Global();
 };
 
 TEST_F(ImTester, AddTablet) {
diff --git a/visualdl/backend/logic/pybind.cc b/visualdl/backend/logic/pybind.cc
index b6ff06f1aa1ab0985e475ba3e9973e322f7ac207..9b7f67727afc657b21b4274bf79cb6ffae94f4c7 100644
--- a/visualdl/backend/logic/pybind.cc
+++ b/visualdl/backend/logic/pybind.cc
@@ -55,7 +55,14 @@ PYBIND11_PLUGIN(core) {
       .def("persist_to_disk", &vs::ImHelper::PersistToDisk)
       .def("clear_tablets", &vs::ImHelper::ClearTablets);
 
-  m.def("im", &vs::get_im, "global information-maintainer object.");
+  m.def("start_read_service",
+        &vs::start_read_service,
+        "global information-maintainer object.");
+  m.def("start_write_service",
+        &vs::start_write_service,
+        "global information-maintainer object.");
+  m.def("im", &vs::im);
+  m.def("stop_threads", &vs::StopThreads);
 
 // 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 c676c5505ab215ca6e601b8307af443520238f2f..4ce6362fbcf1e9b5f07d987e7a3988d11888d64e 100644
--- a/visualdl/backend/logic/sdk.cc
+++ b/visualdl/backend/logic/sdk.cc
@@ -60,9 +60,7 @@ std::string TabletHelper::human_readable_buffer() const {
   return buffer;
 }
 
-void ImHelper::PersistToDisk() const {
-  InformationMaintainer::Global().PersistToDisk();
-}
+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 5162fee8c0bcae538cabd790d9c68e2361a79dff..e97d4f85d8d7b558bf4e55b611914f8f502dad1b 100644
--- a/visualdl/backend/logic/sdk.h
+++ b/visualdl/backend/logic/sdk.h
@@ -77,7 +77,10 @@ public:
 
   void SetBuffer(const storage::Storage &buffer) { *data_ = buffer; }
   void SetBuffer(const std::string &buffer) { data_->ParseFromString(buffer); }
-  void SetDir(const std::string &dir) { data_->set_dir(dir); }
+  void SetDir(const std::string &dir) {
+    CHECK(data_) << "no storage instance hold";
+    data_->set_dir(dir);
+  }
 
   int64_t timestamp() const { return data_->timestamp(); }
   std::string dir() const { return data_->dir(); }
@@ -86,64 +89,19 @@ public:
   std::string human_readable_buffer() const;
 
 private:
-  storage::Storage *data_;
+  storage::Storage *data_{nullptr};
 };
 
 class ImHelper {
 public:
   ImHelper() {}
 
-  StorageHelper storage() {
-    return StorageHelper(
-        InformationMaintainer::Global().storage().mutable_data());
-  }
-  TabletHelper tablet(const std::string &tag) {
-    return TabletHelper(InformationMaintainer::Global().storage().tablet(tag));
-  }
-  TabletHelper AddTablet(const std::string &tag, int num_samples) {
-    return TabletHelper(
-        InformationMaintainer::Global().AddTablet(tag, num_samples));
-  }
-  void ClearTablets() {
-    InformationMaintainer::Global().storage().mutable_data()->clear_tablets();
-  }
-
-  void PersistToDisk() const;
-};
-
-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 &get_im() {
-  static ImHelper im;
-  return im;
+  /*
+   * mode:
+   * 0: read
+   * 1: write
+   * 2: none
+   */
 }
 
 }  // namespace visualdl
diff --git a/visualdl/backend/python/summary.py b/visualdl/backend/python/summary.py
index 59877aca69df649599e55aa112a4a8cf9d26c107..13b9400c3f358529d72d7057ac3f55ae6488c538 100644
--- a/visualdl/backend/python/summary.py
+++ b/visualdl/backend/python/summary.py
@@ -4,8 +4,6 @@ __all__ = [
 ]
 import core
 
-im = core.im()
-
 dtypes = ("float", "double", "int32", "int64")
 
 
@@ -15,7 +13,19 @@ def set_storage(dir):
         directory of summary to write log.
     :return: None
     '''
-    im.storage().set_dir(dir)
+    core.im().storage().set_dir(dir)
+
+
+def set_readable_storage(dir):
+    core.start_read_service(dir)
+
+
+def set_writable_storage(dir):
+    core.start_write_service(dir)
+
+
+def stop_service():
+    core.stop_threads()
 
 
 class _Scalar(object):
@@ -95,7 +105,19 @@ def scalar(tag, dtype='float'):
     '''
     assert dtype in dtypes, "invalid dtype(%s), should be one of %s" % (
         dtype, str(dtypes))
-    tablet = im.add_tablet(tag, -1)
+    tablet = core.im().add_tablet(tag, -1)
+    dtype2obj = {
+        'float': tablet.as_float_scalar,
+        'double': tablet.as_double_scalar,
+        'int32': tablet.as_int32_scalar,
+        'int64': tablet.as_int64_scalar,
+    }
+    obj = dtype2obj[dtype]()
+    return _Scalar(obj)
+
+
+def read_scalar(tag, dtype='float'):
+    tablet = core.im().tablet(tag)
     dtype2obj = {
         'float': tablet.as_float_scalar,
         'double': tablet.as_double_scalar,
diff --git a/visualdl/backend/python/test_read_service.py b/visualdl/backend/python/test_read_service.py
new file mode 100644
index 0000000000000000000000000000000000000000..0831e04b103d899c59a5d3406b0dcea6b99a90b3
--- /dev/null
+++ b/visualdl/backend/python/test_read_service.py
@@ -0,0 +1,15 @@
+import summary
+import numpy as np
+import unittest
+import time
+
+
+class StorageTester(unittest.TestCase):
+    def test_storage(self):
+        summary.set_writable_storage("./tmp_dir")
+        time.sleep(5)
+        summary.stop_service()
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/visualdl/backend/python/test_summary.py b/visualdl/backend/python/test_summary.py
index 24fec43f5690da88c4d0d8fd2bad697794e4b032..c3caab75052cd04b3ff5b792a7c85988905d2fd8 100644
--- a/visualdl/backend/python/test_summary.py
+++ b/visualdl/backend/python/test_summary.py
@@ -1,14 +1,14 @@
 import summary
 import numpy as np
 import unittest
-
-summary.set_storage("tmp_dir")
+import time
 
 once_flag = False
 
 
 class ScalarTester(unittest.TestCase):
     def setUp(self):
+        summary.set_storage("tmp_dir")
         global once_flag
         self.scalar = summary.scalar("scalar0")
         if not once_flag:
diff --git a/visualdl/backend/python/test_write_service.py b/visualdl/backend/python/test_write_service.py
new file mode 100644
index 0000000000000000000000000000000000000000..241869c47786a19288b52b6abcd0d9c21cdb788c
--- /dev/null
+++ b/visualdl/backend/python/test_write_service.py
@@ -0,0 +1,17 @@
+import summary
+import numpy as np
+import unittest
+import time
+
+
+class StorageTester(unittest.TestCase):
+    def test_read_storage(self):
+        summary.set_readable_storage("./tmp")
+        time.sleep(1)
+        scalar = summary.read_scalar('tag01')
+        time.sleep(5)
+        summary.stop_service()
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/visualdl/backend/storage/storage.cc b/visualdl/backend/storage/storage.cc
index ca45d80142443ba86b4ed208242ed9b44b64c078..9ed2e20e245d72aba003ce4074bb684c69e11a2f 100644
--- a/visualdl/backend/storage/storage.cc
+++ b/visualdl/backend/storage/storage.cc
@@ -1,4 +1,5 @@
 #include <glog/logging.h>
+#include <visualdl/backend/utils/concurrency.h>
 #include <fstream>
 
 #include "visualdl/backend/storage/storage.h"
@@ -6,12 +7,17 @@
 
 namespace visualdl {
 
-std::string GenPathFromTag(const std::string &dir, const std::string &tag) {
-  return dir + "/" + tag;
-}
-
 const std::string StorageBase::meta_file_name = "storage.meta";
 
+std::string StorageBase::meta_path() const {
+  CHECK(!storage_.dir().empty()) << "storage.dir should be set first";
+  return storage_.dir() + "/" + meta_file_name;
+}
+std::string StorageBase::tablet_path(const std::string &tag) const {
+  CHECK(!storage_.dir().empty()) << "storage.dir should be set first";
+  return storage_.dir() + "/" + tag;
+}
+
 storage::Tablet *MemoryStorage::NewTablet(const std::string &tag,
                                           int num_samples) {
   auto it = tablets_.find(tag);
@@ -32,39 +38,54 @@ storage::Tablet *MemoryStorage::tablet(const std::string &tag) {
   return &it->second;
 }
 
+// TODO add some checksum to avoid unnecessary saving
 void MemoryStorage::PersistToDisk() const {
+  CHECK(!storage_.dir().empty()) << "storage's dir should be set first";
   VLOG(3) << "persist storage to disk path " << storage_.dir();
   // make a directory if not exist
   fs::TryMkdir(storage_.dir());
   // write storage out
-  CHECK(!storage_.dir().empty()) << "storage's dir should be set first";
-  const auto meta_path = storage_.dir() + "/" + meta_file_name;
-  fs::Write(meta_path, fs::Serialize(storage_));
+  fs::SerializeToFile(storage_, meta_path());
   // write all the tablets
   for (auto tag : storage_.tags()) {
-    auto path = GenPathFromTag(storage_.dir(), tag);
     auto it = tablets_.find(tag);
     CHECK(it != tablets_.end());
-    fs::Write(path, fs::Serialize(it->second));
+    fs::SerializeToFile(it->second, tablet_path(tag));
   }
 }
 
+// TODO add some checksum to avoid unnecessary loading
 void MemoryStorage::LoadFromDisk(const std::string &dir) {
-  VLOG(3) << "load storage from disk path " << dir;
   CHECK(!dir.empty()) << "dir is empty";
+  storage_.set_dir(dir);
   // load storage
-  const auto meta_path = dir + "/" + meta_file_name;
-  auto buf = fs::Read(meta_path);
-  CHECK(fs::DeSerialize(&storage_, buf))
-      << "failed to parse protobuf loaded from " << meta_path;
+  CHECK(fs::DeSerializeFromFile(&storage_, meta_path()))
+      << "parse from " << meta_path() << " failed";
 
   // load all the tablets
   for (int i = 0; i < storage_.tags_size(); i++) {
-    std::string tag = storage_.tags(i);
-    auto path = GenPathFromTag(storage_.dir(), tag);
-    CHECK(tablets_[tag].ParseFromString(fs::Read(path)))
-        << "failed to parse protobuf text loaded from " << path;
+    auto tag = storage_.tags(i);
+    CHECK(fs::DeSerializeFromFile(&tablets_[tag], tablet_path(tag)));
   }
 }
 
+void MemoryStorage::StartReadService() {
+  cc::PeriodExector::task_t task = [this] {
+    VLOG(3) << "loading from " << storage_.dir();
+    LoadFromDisk(storage_.dir());
+    return true;
+  };
+  cc::PeriodExector::Global().Start();
+  VLOG(3) << "push read task";
+  cc::PeriodExector::Global()(std::move(task), 2512);
+}
+
+void MemoryStorage::StartWriteSerice() {
+  cc::PeriodExector::Global().Start();
+  cc::PeriodExector::task_t task = [this] {
+    PersistToDisk();
+    return true;
+  };
+  cc::PeriodExector::Global()(std::move(task), 2000);
+}
 }  // namespace visualdl
diff --git a/visualdl/backend/storage/storage.h b/visualdl/backend/storage/storage.h
index d9e8ae29a2481a7301b8e6740763abb91c76889c..a827a6dbd8d936ff6f9c8de9c95289cd8cbff0ee 100644
--- a/visualdl/backend/storage/storage.h
+++ b/visualdl/backend/storage/storage.h
@@ -26,6 +26,8 @@ public:
   const static std::string meta_file_name;
 
   enum Type { kMemory = 0, kDisk = 1 };
+  // mode of the sevice, either reading or writing.
+  enum Mode { kRead = 0, kWrite = 1, kNone = 2 };
 
   void SetStorage(const std::string &dir) {
     time_t t;
@@ -34,6 +36,9 @@ public:
     storage_.set_dir(dir);
   }
 
+  std::string meta_path() const;
+  std::string tablet_path(const std::string &tag) const;
+
   /*
    * Create a new Tablet storage.
    */
@@ -78,6 +83,18 @@ public:
 
   void LoadFromDisk(const std::string &dir) override;
 
+  /*
+   * Create a thread which will keep reading the latest data from the disk to
+   * memory.
+   */
+  void StartReadService();
+
+  /*
+   * Create a thread which will keep writing the latest changes from memory to
+   * disk.
+   */
+  void StartWriteSerice();
+
 private:
   std::map<std::string, storage::Tablet> tablets_;
 };
diff --git a/visualdl/backend/storage/storage_test.cc b/visualdl/backend/storage/storage_test.cc
index 6090d71f4b4ac88379f9eacce3a01f01434ecff9..91c2a59d47ed38f8f6a6eb5affc27305171bbf92 100644
--- a/visualdl/backend/storage/storage_test.cc
+++ b/visualdl/backend/storage/storage_test.cc
@@ -32,6 +32,8 @@ TEST_F(MemoryStorageTest, AddTablet) {
 }
 
 TEST_F(MemoryStorageTest, PersistToDisk) {
+  storage_.SetStorage("./tmp");
+  CHECK(!storage_.data().dir().empty());
   string tag = "add%20tag0";
   storage_.NewTablet(tag, -1);
 
diff --git a/visualdl/backend/utils/concurrency.h b/visualdl/backend/utils/concurrency.h
new file mode 100644
index 0000000000000000000000000000000000000000..a3d46a9a89df99ca73c1075216be71990bbd34b3
--- /dev/null
+++ b/visualdl/backend/utils/concurrency.h
@@ -0,0 +1,61 @@
+#ifndef VISUALDL_BACKEND_UTILS_CONCURRENCY_H
+#define VISUALDL_BACKEND_UTILS_CONCURRENCY_H
+
+#include <glog/logging.h>
+#include <chrono>
+#include <memory>
+#include <thread>
+#include <vector>
+
+namespace visualdl {
+namespace cc {
+
+/*
+ * Run a task every `duration` milliseconds.
+ * Each evoke will start a thread to do this asynchronously.
+ */
+struct PeriodExector {
+  using task_t = std::function<bool()>;
+
+  static PeriodExector& Global() {
+    static PeriodExector exec;
+    return exec;
+  }
+
+  void Quit() {
+    // TODO use some conditonal variable to help quit immediately.
+    quit = true;
+  }
+
+  void Start() { quit = false; }
+
+  void operator()(task_t&& task, int msec) {
+    auto task_wrapper = [=] {
+      while (!quit) {
+        if (!task()) break;
+        std::this_thread::sleep_for(std::chrono::milliseconds(msec));
+      }
+      LOG(INFO) << "quit job";
+    };
+    threads_.emplace_back(std::thread(std::move(task_wrapper)));
+    msec_ = msec;
+  }
+
+  ~PeriodExector() {
+    for (auto& t : threads_) {
+      if (t.joinable()) {
+        t.join();
+      }
+    }
+  }
+
+private:
+  bool quit = false;
+  std::vector<std::thread> threads_;
+  int msec_;
+};
+
+}  // namespace cc
+}  // namespace visualdl
+
+#endif
diff --git a/visualdl/backend/utils/filesystem.h b/visualdl/backend/utils/filesystem.h
index e30640b97bbf9509b78cc3ef55e7569bfd9bf7c8..9a509407c12816f77a2a97f1d2ed5e2972a7c531 100644
--- a/visualdl/backend/utils/filesystem.h
+++ b/visualdl/backend/utils/filesystem.h
@@ -30,6 +30,18 @@ bool DeSerialize(T* proto, const std::string buf, bool human_readable = false) {
   return proto->ParseFromString(buf);
 }
 
+template <typename T>
+bool SerializeToFile(const T& proto, const std::string& path) {
+  std::ofstream file(path, std::ios::binary);
+  return proto.SerializeToOstream(&file);
+}
+
+template <typename T>
+bool DeSerializeFromFile(T* proto, const std::string& path) {
+  std::ifstream file(path, std::ios::binary);
+  return proto->ParseFromIstream(&file);
+}
+
 void TryMkdir(const std::string& dir) {
   VLOG(1) << "try to mkdir " << dir;
   struct stat st = {0};
diff --git a/visualdl/backend/utils/log.h b/visualdl/backend/utils/log.h
new file mode 100644
index 0000000000000000000000000000000000000000..9aed0806d905079b09e37734224bbf2ddb3b376c
--- /dev/null
+++ b/visualdl/backend/utils/log.h
@@ -0,0 +1,18 @@
+#ifndef VISUALDL_BACKEND_UTILS_LOG_H
+#define VISUALDL_BACKEND_UTILS_LOG_H
+
+#include <stdexcept>
+namespace visualdl {
+
+namespace log {
+
+class NotImplementedException : public std::logic_error {
+public:
+  NotImplementedException() : std::logic_error{"Function not implemented"} {}
+};
+
+}  // namespace log
+
+}  // namespace visualdl
+
+#endif
diff --git a/visualdl/backend/utils/test_concurrency.cc b/visualdl/backend/utils/test_concurrency.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9657e2d31e16453a790cf052703605da389999a2
--- /dev/null
+++ b/visualdl/backend/utils/test_concurrency.cc
@@ -0,0 +1,19 @@
+#include "visualdl/backend/utils/concurrency.h"
+
+#include <glog/logging.h>
+#include <gtest/gtest.h>
+
+namespace visualdl {
+
+int counter = 0;
+
+TEST(concurrency, test) {
+  cc::PeriodExector::task_t task = [&counter]() {
+    LOG(INFO) << "Hello " << counter++;
+    if (counter > 5) return false;
+    return true;
+  };
+  cc::PeriodExector::Global()(std::move(task), 200);
+}
+
+}  // namespace visualdl
\ No newline at end of file