diff --git a/Test/Test.vcxproj b/Test/Test.vcxproj
index 01ed1e3..81a2309 100644
--- a/Test/Test.vcxproj
+++ b/Test/Test.vcxproj
@@ -83,7 +83,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>IMultiverso.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies);</AdditionalDependencies>
+      <AdditionalDependencies>Multiverso.lib;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies);</AdditionalDependencies>
       <AdditionalLibraryDirectories>D:\multiverso-next\x64\release</AdditionalLibraryDirectories>
     </Link>
     <ProjectReference>
diff --git a/Test/main.cpp b/Test/main.cpp
index 2f2aafa..adf1f9e 100644
--- a/Test/main.cpp
+++ b/Test/main.cpp
@@ -10,6 +10,7 @@
 #include <multiverso/net.h>
 #include <multiverso/util/log.h>
 #include <multiverso/util/net_util.h>
+#include <multiverso/util/configure.h>
 
 #include <multiverso/table/array_table.h>
 #include <multiverso/table/kv_table.h>
@@ -112,7 +113,6 @@ void TestArray(int argc, char* argv[]) {
       std::cout << data[i] << " "; std::cout << std::endl;
     MV_Barrier();
 
-    if (iter % 100 == 0) MV_Dashboard();
   }
   MV_ShutDown();
 }
@@ -157,52 +157,52 @@ void TestArray(int argc, char* argv[]) {
 #define ARRAY_SIZE 4683776
 void TestMultipleThread(int argc, char* argv[])
 {
-	Log::Info("Test Multiple threads \n");
-	std::mt19937_64 eng{ std::random_device{}() };  
-	std::uniform_int_distribution<> dist{ 5, 10000 };
-	std::this_thread::sleep_for(std::chrono::milliseconds{ dist(eng) });
-	//Log::ResetLogLevel(LogLevel::Debug);
-	MV_Init(&argc, argv);
+  Log::Info("Test Multiple threads \n");
+  std::mt19937_64 eng{ std::random_device{}() };
+  std::uniform_int_distribution<> dist{ 5, 10000 };
+  std::this_thread::sleep_for(std::chrono::milliseconds{ dist(eng) });
+  //Log::ResetLogLevel(LogLevel::Debug);
+  MV_Init(&argc, argv);
 
-	ArrayWorker<float>* shared_array = new ArrayWorker<float>(ARRAY_SIZE);
-	ArrayServer<float>* server_array = new ArrayServer<float>(ARRAY_SIZE);
-	std::thread* m_prefetchThread = nullptr;
-	MV_Barrier();
-	Log::Info("Create tables OK\n");
+  ArrayWorker<float>* shared_array = new ArrayWorker<float>(ARRAY_SIZE);
+  ArrayServer<float>* server_array = new ArrayServer<float>(ARRAY_SIZE);
+  std::thread* m_prefetchThread = nullptr;
+  MV_Barrier();
+  Log::Info("Create tables OK\n");
 
-	std::vector<float> delta(ARRAY_SIZE);
-	while (true){
-		if (m_prefetchThread != nullptr && m_prefetchThread->joinable())
-		{
-			m_prefetchThread->join();
-			delete m_prefetchThread;
-			m_prefetchThread = nullptr;
-		}
+  std::vector<float> delta(ARRAY_SIZE);
+  while (true){
+    if (m_prefetchThread != nullptr && m_prefetchThread->joinable())
+    {
+      m_prefetchThread->join();
+      delete m_prefetchThread;
+      m_prefetchThread = nullptr;
+    }
 
-		std::fill(delta.begin(), delta.end(), 0);
-		for (int i = 0; i < ARRAY_SIZE; ++i)
-		{
-		std::mt19937_64 eng{ std::random_device{}() };
-			std::uniform_real_distribution<float> dist{ -1, 1 };
-			delta[i] = dist(eng);
-		}
-		m_prefetchThread = new std::thread([&](){
-			
-			//std::mt19937_64 eng{ std::random_device{}() };  
-			//std::uniform_int_distribution<> dist{ 50, 500 };
-			//std::this_thread::sleep_for(std::chrono::milliseconds{ dist(eng) });
-			shared_array->Add(delta.data(), ARRAY_SIZE);
-			shared_array->Get(delta.data(), ARRAY_SIZE);
-			Log::Info("Rank %d Get OK\n", MV_Rank());
-			for (int i = 0; i < 10; ++i)
-				std::cout << delta[i] << " "; std::cout << std::endl;
-		});
+    std::fill(delta.begin(), delta.end(), 0);
+    for (int i = 0; i < ARRAY_SIZE; ++i)
+    {
+      std::mt19937_64 eng{ std::random_device{}() };
+      std::uniform_real_distribution<float> dist{ -1, 1 };
+      delta[i] = dist(eng);
+    }
+    m_prefetchThread = new std::thread([&](){
 
-		//shared_array->Get(data, 10);
-		MV_Barrier();
+      //std::mt19937_64 eng{ std::random_device{}() };  
+      //std::uniform_int_distribution<> dist{ 50, 500 };
+      //std::this_thread::sleep_for(std::chrono::milliseconds{ dist(eng) });
+      shared_array->Add(delta.data(), ARRAY_SIZE);
+      shared_array->Get(delta.data(), ARRAY_SIZE);
+      Log::Info("Rank %d Get OK\n", MV_Rank());
+      for (int i = 0; i < 10; ++i)
+        std::cout << delta[i] << " "; std::cout << std::endl;
+    });
 
-	}
-	MV_ShutDown();
+    //shared_array->Get(data, 10);
+    MV_Barrier();
+
+  }
+  MV_ShutDown();
 }
 
 
@@ -230,7 +230,7 @@ void TestNet(int argc, char* argv[]) {
       for (int i = 0; i < msg->size(); ++i) {
         Log::Info("In Send: %s\n", msg->data()[i].data());
       };
-      while (net->Send(msg) == 0) ;
+      while (net->Send(msg) == 0);
       Log::Info("rank 0 send\n");
     }
 
@@ -248,7 +248,8 @@ void TestNet(int argc, char* argv[]) {
         Log::Info("recv from srv %d: %s\n", msg->src(), recv_data[i].data());
       };
     }
-  } else {// other rank
+  }
+  else {// other rank
     MessagePtr msg(new Message());// = std::make_unique<Message>();
     while (net->Recv(&msg) == 0) {
       // Log::Info("recv return 0\n");
@@ -267,7 +268,7 @@ void TestNet(int argc, char* argv[]) {
     msg->Push(Blob(hi1, 13));
     msg->Push(Blob(hi2, 11));
     msg->Push(Blob(hi3, 18));
-    while (net->Send(msg) == 0) ;
+    while (net->Send(msg) == 0);
     Log::Info("rank %d send\n", net->rank());
   }
   // while (!net->Test()) {
@@ -283,7 +284,7 @@ void TestIP() {
   for (auto ip : ip_list) Log::Info("%s\n", ip.c_str());
 }
 
-void TestNoNet(int argc, char* argv[]) {  
+void TestNoNet(int argc, char* argv[]) {
   int provided;
   MPI_Init_thread(&argc, &argv, MPI_THREAD_SERIALIZED, &provided);
 
@@ -329,90 +330,90 @@ void TestNoNet(int argc, char* argv[]) {
 }
 
 void TestMatrix(int argc, char* argv[]){
-	Log::Info("Test Matrix\n");
+  Log::Info("Test Matrix\n");
 
-	MV_Init(&argc, argv);
+  MV_Init(&argc, argv);
 
-	int num_row = 11, num_col = 10;
-	int size = num_row * num_col;
+  int num_row = 11, num_col = 10;
+  int size = num_row * num_col;
 
   // MatrixWorkerTable<int>* worker_table = 
-    // static_cast<MatrixWorkerTable<int>*>(MV_CreateTable<int>("matrix", { &num_row, &num_col }));  //new implementation
+  // static_cast<MatrixWorkerTable<int>*>(MV_CreateTable<int>("matrix", { &num_row, &num_col }));  //new implementation
   //  static_cast<MatrixWorkerTable<int>*>((new MatrixTableHelper<int>(num_row, num_col))->CreateTable()); //older one
 
   //if (worker_table == nullptr){ //should have more if statement to avoid nullptr in using worker_table
   //  Log::Debug("rank %d has no worker\n", MV_Rank());
   // }
 
-	MatrixWorkerTable<float>* worker_table = new MatrixWorkerTable<float>(num_row, num_col);
-	MatrixServerTable<float>* server_table = new MatrixServerTable<float>(num_row, num_col);
-	std::thread* m_prefetchThread = nullptr;
-	MV_Barrier();
+  MatrixWorkerTable<float>* worker_table = new MatrixWorkerTable<float>(num_row, num_col);
+  MatrixServerTable<float>* server_table = new MatrixServerTable<float>(num_row, num_col);
+  std::thread* m_prefetchThread = nullptr;
+  MV_Barrier();
 
-	while (true)
-	{
-		if (m_prefetchThread != nullptr && m_prefetchThread->joinable())
-		{
-			m_prefetchThread->join();
-			delete m_prefetchThread;
-			m_prefetchThread = nullptr;
-		}
-		std::vector<int> v = { 0, 1, 5, 10 };
+  while (true)
+  {
+    if (m_prefetchThread != nullptr && m_prefetchThread->joinable())
+    {
+      m_prefetchThread->join();
+      delete m_prefetchThread;
+      m_prefetchThread = nullptr;
+    }
+    std::vector<int> v = { 0, 1, 5, 10 };
 
-		// test data
-		std::vector<float> delta(size);
-		for (int i = 0; i < size; ++i)
-			delta[i] = i;
+    // test data
+    std::vector<float> delta(size);
+    for (int i = 0; i < size; ++i)
+      delta[i] = i;
 
-		float * data = new float[size];
-		m_prefetchThread = new std::thread([&](){
+    float * data = new float[size];
+    m_prefetchThread = new std::thread([&](){
 
       UpdateOption option;
-			worker_table->Add(delta.data(), size, &option); //add all
+      worker_table->Add(delta.data(), size, &option); //add all
 
-			worker_table->Get(data, size); //get all
-			printf("----------------------------\n");
-			for (int i = 0; i < num_row; ++i){
-				printf("rank %d, row %d: ", MV_Rank(), i);
-				for (int j = 0; j < num_col; ++j)
-					printf("%.2f ", data[i * num_col + j]);
-				printf("\n");
-			};
-		});
+      worker_table->Get(data, size); //get all
+      printf("----------------------------\n");
+      for (int i = 0; i < num_row; ++i){
+        printf("rank %d, row %d: ", MV_Rank(), i);
+        for (int j = 0; j < num_col; ++j)
+          printf("%.2f ", data[i * num_col + j]);
+        printf("\n");
+      };
+    });
 
-		MV_Barrier();
-		if (m_prefetchThread != nullptr && m_prefetchThread->joinable())
-		{
-			m_prefetchThread->join();
-			delete m_prefetchThread;
-			m_prefetchThread = nullptr;
-		}
-		//test data_vec
-		std::vector<float*> data_rows = { &data[0], &data[num_col], &data[5 * num_col], &data[10 * num_col] };
-		std::vector<float*> delta_rows = { &delta[0], &delta[num_col], &delta[5 * num_col], &delta[10 * num_col] };
+    MV_Barrier();
+    if (m_prefetchThread != nullptr && m_prefetchThread->joinable())
+    {
+      m_prefetchThread->join();
+      delete m_prefetchThread;
+      m_prefetchThread = nullptr;
+    }
+    //test data_vec
+    std::vector<float*> data_rows = { &data[0], &data[num_col], &data[5 * num_col], &data[10 * num_col] };
+    std::vector<float*> delta_rows = { &delta[0], &delta[num_col], &delta[5 * num_col], &delta[10 * num_col] };
     UpdateOption option;
-		worker_table->Add(v, delta_rows, num_col, &option);
-		worker_table->Get(v, data_rows, num_col);
-		MV_Barrier();
+    worker_table->Add(v, delta_rows, num_col, &option);
+    worker_table->Get(v, data_rows, num_col);
+    MV_Barrier();
 
-		printf("----------------------------\n");
-		for (int i = 0; i < num_row; ++i){
-			printf("rank %d, row %d: ", MV_Rank(), i);
-			for (int j = 0; j < num_col; ++j)
-				printf("%.2f ", data[i * num_col + j]);
-			printf("\n");
-		}
-		MV_Barrier();
+    printf("----------------------------\n");
+    for (int i = 0; i < num_row; ++i){
+      printf("rank %d, row %d: ", MV_Rank(), i);
+      for (int j = 0; j < num_col; ++j)
+        printf("%.2f ", data[i * num_col + j]);
+      printf("\n");
+    }
+    MV_Barrier();
 
-	}
-	MV_ShutDown();
+  }
+  MV_ShutDown();
 }
 
 // NOTE(feiga): this doesn't work now since I roll back some implementation
 void TestCheckPoint(int argc, char* argv[], bool restore){
   Log::Info("Test CheckPoint\n");
 
-  MV_Init(&argc, argv, 3 /*, restore */);
+  MV_Init(&argc, argv);
 
   int num_row = 11, num_col = 10;
   int size = num_row * num_col;
@@ -453,19 +454,25 @@ void TestCheckPoint(int argc, char* argv[], bool restore){
   MV_ShutDown();
 }
 
-void TestComm(int argc, char* argv[]) {
-
+void TestAllreduce(int argc, char* argv[]) {
+  multiverso::SetCMDFlag("ps_role", std::string("none"));
+  MV_Init(&argc, argv);
+  int a = 1;
+  MV_Aggregate(&a, 1);
+  std::cout << "a = " << a << std::endl;
+  MV_ShutDown();
 }
 
+
 int main(int argc, char* argv[]) {
   Log::ResetLogLevel(LogLevel::Debug);
 
   if (argc == 1){
-      multiverso::MV_Init();
-      ::testing::InitGoogleTest(&argc, argv);
-      auto res = RUN_ALL_TESTS();
-      multiverso::MV_ShutDown();
-      return res;
+    multiverso::MV_Init();
+    ::testing::InitGoogleTest(&argc, argv);
+    auto res = RUN_ALL_TESTS();
+    multiverso::MV_ShutDown();
+    return res;
   }
   else {
     if (strcmp(argv[1], "kv") == 0) TestKV(argc, argv);
@@ -477,6 +484,7 @@ int main(int argc, char* argv[]) {
     else if (strcmp(argv[1], "nonet") == 0) TestNoNet(argc, argv);
     else if (strcmp(argv[1], "checkpoint") == 0)  TestCheckPoint(argc, argv, false);
     else if (strcmp(argv[1], "restore") == 0) TestCheckPoint(argc, argv, true);
+    else if (strcmp(argv[1], "allreduce") == 0) TestAllreduce(argc, argv);
     else CHECK(false);
   }
   return 0;
diff --git a/include/multiverso/multiverso.h b/include/multiverso/multiverso.h
index 01a261f..510d2d3 100644
--- a/include/multiverso/multiverso.h
+++ b/include/multiverso/multiverso.h
@@ -5,13 +5,11 @@
 
 namespace multiverso {
 
-void MV_Init(int* argc = nullptr,
-             char* argv[] = nullptr,
-             int role = 3);
+void MV_Init(int* argc = nullptr, char* argv[] = nullptr);
 
 void MV_Barrier();
 
-void MV_ShutDown(bool finalize_mpi = true);
+void MV_ShutDown(bool finalize_net = true);
 
 int  MV_Rank();
 int  MV_Size();
@@ -25,9 +23,9 @@ int  MV_ServerId();
 int  MV_WorkerIdToRank(int worker_id);
 int  MV_ServerIdToRank(int server_id);
 
-// Show the dashboard information about the monitored excuation time
-// used for profile
-void MV_Dashboard();
+// inplace sum by allreduce
+template <typename ElemType>
+void MV_Aggregate(ElemType* data, int size);
 
 // --- Net API -------------------------------------------------------------- //
 // NOTE(feiga): these API is only used for specific situation.
diff --git a/include/multiverso/net.h b/include/multiverso/net.h
index 150b321..a907ce2 100644
--- a/include/multiverso/net.h
+++ b/include/multiverso/net.h
@@ -32,6 +32,8 @@ public:
   virtual int size() const = 0;
   virtual int rank() const = 0;
 
+  // virtual void Allreduce(void* data, size_t count, int type, int type_size);
+
   // \return 1. > 0 sended size
   //         2. = 0 not sended
   //         3. < 0 net error
@@ -45,6 +47,12 @@ public:
   virtual int thread_level_support() = 0;
 };
 
+namespace net {
+// inplace allreduce
+template <typename Typename>
+void Allreduce(Typename* data, size_t elem_count);
+}
+
 }  // namespace multiverso
 
 #endif  // MULTIVERSO_NET_NET_H_
diff --git a/include/multiverso/net/mpi_net.h b/include/multiverso/net/mpi_net.h
index 2e58dc2..fd49181 100644
--- a/include/multiverso/net/mpi_net.h
+++ b/include/multiverso/net/mpi_net.h
@@ -70,6 +70,7 @@ public:
     MV_MPI_CALL(MPI_Initialized(&inited_));
     if (!inited_) {
       MV_MPI_CALL(MPI_Init_thread(argc, &argv, MPI_THREAD_SERIALIZED, &thread_provided_));
+      MV_MPI_CALL(MPI_Initialized(&inited_));
     }
     MV_MPI_CALL(MPI_Query_thread(&thread_provided_));
     if (thread_provided_ < MPI_THREAD_SERIALIZED) {
@@ -105,6 +106,9 @@ public:
   int size() const override { return size_; }
   std::string name() const override { return "MPI"; }
 
+  template <typename ElemType>
+  static void Allreduce(ElemType* data, size_t elem_count, int op = MPI_SUM);
+
   //size_t Send(MessagePtr& msg) override {
   //  while (!msg_handles_.empty()) {
   //    MPIMsgHandle* prev = msg_handles_.front();
diff --git a/include/multiverso/node.h b/include/multiverso/node.h
index a11cd42..9f3155d 100644
--- a/include/multiverso/node.h
+++ b/include/multiverso/node.h
@@ -4,15 +4,16 @@
 namespace multiverso {
 
 enum Role {
+  NONE   = 0,
   WORKER = 1,
-  SERVER = 2
+  SERVER = 2,
+  ALL    = 3
 };
 
 struct Node {
   int rank;
   // role can be 0, 1, 2, 3
-  // 00 means neither worker nor server, should be controllor, so at most
-  // one node could use this value
+  // 00 means neither worker nor server
   // 01 means worker
   // 10 means server
   // 11 means both server and worker, default value
diff --git a/include/multiverso/server.h b/include/multiverso/server.h
index fed650a..7c83832 100644
--- a/include/multiverso/server.h
+++ b/include/multiverso/server.h
@@ -9,21 +9,17 @@
 namespace multiverso {
 
 class ServerTable;
+class Synchronizer;
 
 class Server : public Actor {
 public:
   Server();
   int RegisterTable(ServerTable* table);
-  // store server data to file
-  void StoreTable(int epoch);
-  // load data from file and return next iteration number
-  int LoadTable(const std::string& file_path);
-  void SetTableFilePath(const std::string& table_file_path);
 private:
   void ProcessGet(MessagePtr& msg);
   void ProcessAdd(MessagePtr& msg);
-  std::string table_file_path_;
   // contains the parameter data structure and related handle method
+  // Synchronizer* sync_;
   std::vector<ServerTable*> store_;
 };
 
diff --git a/include/multiverso/zoo.h b/include/multiverso/zoo.h
index bc1e565..f6a76c9 100644
--- a/include/multiverso/zoo.h
+++ b/include/multiverso/zoo.h
@@ -24,7 +24,7 @@ public:
   static Zoo* Get() { static Zoo zoo; return &zoo; }
 
   // Start all actors
-  void Start(int* argc, char** argv, int role);
+  void Start(int* argc, char** argv);
   // Stop all actors
   void Stop(bool finalize_net);
 
diff --git a/src/Multiverso.vcxproj b/src/Multiverso.vcxproj
index 0610988..890303b 100644
--- a/src/Multiverso.vcxproj
+++ b/src/Multiverso.vcxproj
@@ -195,7 +195,6 @@
     <ClInclude Include="..\include\multiverso\table_interface.h" />
     <ClInclude Include="..\include\multiverso\updater\adagrad_updater.h" />
     <ClInclude Include="..\include\multiverso\updater\sgd_updater.h" />
-    <ClInclude Include="..\include\multiverso\updater\second_order_gradient_updater.h" />
     <ClInclude Include="..\include\multiverso\updater\momentum_updater.h" />
     <ClInclude Include="..\include\multiverso\updater\updater.h" />
     <ClInclude Include="..\include\multiverso\util\configure.h" />
@@ -221,6 +220,7 @@
     <ClCompile Include="net.cpp" />
     <ClCompile Include="net\allreduce_engine.cpp" />
     <ClCompile Include="net\allreduce_topo.cpp" />
+    <ClCompile Include="net\mpi_net.cpp" />
     <ClCompile Include="node.cpp" />
     <ClCompile Include="server.cpp" />
     <ClCompile Include="table.cpp" />
diff --git a/src/Multiverso.vcxproj.filters b/src/Multiverso.vcxproj.filters
index d929ffc..75165dd 100644
--- a/src/Multiverso.vcxproj.filters
+++ b/src/Multiverso.vcxproj.filters
@@ -94,9 +94,6 @@
     <ClInclude Include="..\include\multiverso\updater\adagrad_updater.h">
       <Filter>updater</Filter>
     </ClInclude>
-    <ClInclude Include="..\include\multiverso\updater\second_order_gradient_updater.h">
-      <Filter>updater</Filter>
-    </ClInclude>
     <ClInclude Include="..\include\multiverso\table\sparse_matrix_table.h">
       <Filter>table</Filter>
     </ClInclude>
@@ -215,5 +212,8 @@
     <ClCompile Include="io\local_stream.cpp">
       <Filter>io</Filter>
     </ClCompile>
+    <ClCompile Include="net\mpi_net.cpp">
+      <Filter>net</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/src/multiverso.cpp b/src/multiverso.cpp
index d8e8b98..208ba9a 100644
--- a/src/multiverso.cpp
+++ b/src/multiverso.cpp
@@ -6,8 +6,8 @@
 
 namespace multiverso {
 
-void MV_Init(int* argc, char* argv[], int role) {
-  Zoo::Get()->Start(argc, argv, role);
+void MV_Init(int* argc, char* argv[]) {
+  Zoo::Get()->Start(argc, argv);
 }
 
 void MV_ShutDown(bool finalize_net) {
@@ -42,8 +42,9 @@ int  MV_ServerIdToRank(int server_id) {
   return Zoo::Get()->server_id_to_rank(server_id);
 }
 
-void MV_Dashboard() {
-  Dashboard::Display();
+template <typename ElemType>
+void MV_Aggregate(ElemType* data, int size) {
+  net::Allreduce(data, size);
 }
 
 int  MV_NetBind(int rank, char* endpoint) {
@@ -54,4 +55,9 @@ int  MV_NetConnect(int* ranks, char* endpoints[], int size) {
   return NetInterface::Get()->Connect(ranks, endpoints, size);
 }
 
+template void MV_Aggregate<char>(char*, int);
+template void MV_Aggregate<int>(int*, int);
+template void MV_Aggregate<float>(float*, int);
+template void MV_Aggregate<double>(double*, int);
+
 }  // namespace multiverso
diff --git a/src/net.cpp b/src/net.cpp
index 6127cba..24e8164 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -23,4 +23,23 @@ NetInterface* NetInterface::Get() {
 #endif
 }
 
+namespace net {
+template <typename Typename>
+void Allreduce(Typename* data, size_t elem_count) {
+#ifdef MULTIVERSO_USE_MPI
+  CHECK(NetInterface::Get()->active());
+  MPINetWrapper::Allreduce(data, elem_count);
+#else
+
+#endif
+}
+
+template void Allreduce<char>(char*, size_t);
+template void Allreduce<int>(int*, size_t);
+template void Allreduce<float>(float*, size_t);
+template void Allreduce<double>(double*, size_t);
+
+}  // namespace net
+
+
 }  // namespace multiverso
diff --git a/src/net/mpi_net.cpp b/src/net/mpi_net.cpp
new file mode 100644
index 0000000..1083a04
--- /dev/null
+++ b/src/net/mpi_net.cpp
@@ -0,0 +1,23 @@
+#include "multiverso/net/mpi_net.h"
+
+namespace multiverso {
+
+namespace {
+MPI_Datatype GetDataType(char*)   { return MPI_CHAR; }
+MPI_Datatype GetDataType(int*)    { return MPI_INT; }
+MPI_Datatype GetDataType(float*)  { return MPI_FLOAT; }
+MPI_Datatype GetDataType(double*) { return MPI_DOUBLE; }
+}
+
+template <typename ElemType>
+void MPINetWrapper::Allreduce(ElemType* data, size_t elem_count, int op) {
+  MPI_Allreduce(MPI_IN_PLACE, data, (int)elem_count,
+    GetDataType(data), op, MPI_COMM_WORLD);
+}
+
+template void MPINetWrapper::Allreduce<char>(char*, size_t, int);
+template void MPINetWrapper::Allreduce<int>(int*, size_t, int);
+template void MPINetWrapper::Allreduce<float>(float*, size_t, int);
+template void MPINetWrapper::Allreduce<double>(double*, size_t, int);
+
+}  // namespace multiverso
\ No newline at end of file
diff --git a/src/server.cpp b/src/server.cpp
index 00a76a9..b083718 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -44,51 +44,4 @@ void Server::ProcessAdd(MessagePtr& msg) {
   MONITOR_END(SERVER_PROCESS_ADD)
 }
 
-void Server::SetTableFilePath(const std::string& table_file_path) {
-  int id = Zoo::Get()->server_rank();
-  std::string  server_id_str = (id == 0 ? "0" : "");
-  while (id > 0) {
-    server_id_str = static_cast<char>((id % 10) + '0') + server_id_str;
-    id /= 10;
-  }
-  table_file_path_ = table_file_path + server_id_str;
-}
-
-void Server::StoreTable(int epoch) {
-  Stream* stream = StreamFactory::GetStream(URI(table_file_path_),
-                                            FileOpenMode::Write);
-  stream->Write(&epoch, sizeof(int));
-  for (int i = 0; i < store_.size(); ++i) {
-    store_[i]->Store(stream);
-  }
-  delete stream;
-}
-
-int Server::LoadTable(const std::string& file_path) {
-  Stream* stream = StreamFactory::GetStream(URI(table_file_path_),
-                                            FileOpenMode::Read);
-  if (!stream->Good()) {
-    Log::Error("Rank %d open file %s error in Server::LoadTable\n",
-               Zoo::Get()->rank(), file_path.c_str());
-    delete stream;
-    return 0;  //  open file error, may not exist
-  }
-
-  int iter;
-  size_t readsize = stream->Read(&iter, sizeof(int));
-  if (readsize == 0) {
-    Log::Error("Rank %d read file %s no data in Server::LoadTable\n",
-               Zoo::Get()->rank(), file_path.c_str());
-    delete stream;
-    return 0;  // no store data
-  }
-
-  for (int i = 0; i < store_.size(); ++i) {
-    store_[i]->Load(stream);
-  }
-
-  delete stream;
-  return iter + 1;  // the next iteration number
-}
-
 }  // namespace multiverso
diff --git a/src/updater/updater.cpp b/src/updater/updater.cpp
index c9d3a00..98d70da 100644
--- a/src/updater/updater.cpp
+++ b/src/updater/updater.cpp
@@ -2,7 +2,6 @@
 
 #include "multiverso/updater/adagrad_updater.h"
 #include "multiverso/updater/momentum_updater.h"
-#include "multiverso/updater/second_order_gradient_updater.h"
 #include "multiverso/updater/sgd_updater.h"
 #include "multiverso/util/configure.h"
 #include "multiverso/util/log.h"
@@ -35,7 +34,6 @@ Updater<T>* Updater<T>::GetUpdater(size_t size) {
   if (type == "sgd") return new SGDUpdater<T>(size);
   if (type == "adagrad") return new AdaGradUpdater<T>(size);
   if (type == "momentum_sgd") return new MomentumUpdater<T>(size);
-  if (type == "second_order_sgd") return new SecondOrderUpdater<T>(size);
   // Default: simple updater
   return new Updater<T>();
 }
diff --git a/src/zoo.cpp b/src/zoo.cpp
index ad77b0f..8e7c1c5 100644
--- a/src/zoo.cpp
+++ b/src/zoo.cpp
@@ -20,39 +20,59 @@ Zoo::Zoo() {}
 
 Zoo::~Zoo() {}
 
-void Zoo::Start(int* argc, char** argv, int role) {
+MV_DEFINE_string(ps_role, "default", "none / worker / server / default");
+MV_DEFINE_bool(ma, "false", "model average, will not start server if true");
+
+namespace {
+int ParsePSRole(const std::string& ps_role) {
+  if (ps_role == "none")    return Role::NONE;
+  if (ps_role == "worker")  return Role::WORKER; 
+  if (ps_role == "server")  return Role::SERVER;
+  if (ps_role == "default") return Role::ALL;
+  return -1;
+}
+}  // namespace
+
+void Zoo::Start(int* argc, char** argv) {
   Log::Debug("Zoo started\n");
-  CHECK(role >= 0 && role <= 3);
   ParseCMDFlags(argc, argv);
 
   // Init the network
   net_util_ = NetInterface::Get();
   net_util_->Init(argc, argv);
-  nodes_.resize(size());
-  nodes_[rank()].rank = rank();
-  nodes_[rank()].role = role;
-  mailbox_.reset(new MtQueue<MessagePtr>);
 
-  // NOTE(feiga): the start order is non-trivial, communicator should be last.
-  if (rank() == 0) { Actor* controler = new Controller(); controler->Start(); }
-  if (node::is_server(role)) { Actor* server = new Server(); server->Start(); }
-  if (node::is_worker(role)) { Actor* worker = new Worker(); worker->Start(); }
-  Actor* communicator = new Communicator();
-  communicator->Start();
+  if (!MV_CONFIG_ma) {
+    int role = ParsePSRole(MV_CONFIG_ps_role);
+    CHECK(role != -1);
 
-  // activate the system
-  RegisterNode();
-  Log::Info("Rank %d: Zoo start sucessfully\n", rank());
+    nodes_.resize(size());
+    nodes_[rank()].rank = rank();
+    nodes_[rank()].role = role;
+    mailbox_.reset(new MtQueue<MessagePtr>);
+
+    // NOTE(feiga): the start order is non-trivial, communicator should be last.
+    if (rank() == 0) { Actor* controler = new Controller(); controler->Start(); }
+    if (node::is_server(role)) { Actor* server = new Server(); server->Start(); }
+    if (node::is_worker(role)) { Actor* worker = new Worker(); worker->Start(); }
+    Actor* communicator = new Communicator();
+    communicator->Start();
+
+    // activate the system
+    RegisterNode();
+    Log::Info("Rank %d: Zoo start sucessfully\n", rank());
+  }
 }
 
 void Zoo::Stop(bool finalize_net) {
   // Stop the system
-  Barrier();
+  if (!MV_CONFIG_ma) {
+    Barrier();
 
-  Dashboard::Display();
+    Dashboard::Display();
 
-  // Stop all actors
-  for (auto actor : zoo_) { actor.second->Stop(); }
+    // Stop all actors
+    for (auto actor : zoo_) { actor.second->Stop(); }
+  }
   // Stop the network
   if (finalize_net) net_util_->Finalize();
 }