diff --git a/paddle/pserver/ParameterServer2Main.cpp b/paddle/pserver/ParameterServer2Main.cpp
index 114505252211d9a45418e0e298c188785638f1c2..845a2c27e242cfbe31679fea6eae13d2b400ec81 100644
--- a/paddle/pserver/ParameterServer2Main.cpp
+++ b/paddle/pserver/ParameterServer2Main.cpp
@@ -20,10 +20,10 @@ using namespace paddle;  // NOLINT
 int main(int argc, char** argv) {
   initMain(argc, argv);
 
-  std::unique_ptr<ParameterServerController> pServerPtr(
-      paddle::ParameterServerController::createByGflags());
-  pServerPtr->start();
-  pServerPtr->join();
+  std::unique_ptr<ParameterServerController> parameterServerPtr(
+      paddle::ParameterServerController::createFromGflags());
+  parameterServerPtr->start();
+  parameterServerPtr->wait();
 
   return 0;
 }
diff --git a/paddle/pserver/ParameterServerController.cpp b/paddle/pserver/ParameterServerController.cpp
index ec24bc7e573dce2cca484d0deabf4710fd19a25c..1d11a2e1acbc0f091901f3854ca99490d89ebe36 100644
--- a/paddle/pserver/ParameterServerController.cpp
+++ b/paddle/pserver/ParameterServerController.cpp
@@ -25,43 +25,44 @@ ParameterServerController::ParameterServerController(
   int numPorts = config.ports_num() + config.ports_num_for_sparse();
 
   if (config.nics().empty()) {
-    pservers_.resize(numPorts);
+    parameterServers_.resize(numPorts);
     for (int i = 0; i < numPorts; ++i) {
       if (config.rdma_tcp() == "rdma") {
-        pservers_[i].reset(
+        parameterServers_[i].reset(
             new ParameterServer2(std::string(), config.port() + i, rdmaCpu++));
         rdmaCpu = rdmaCpu % onlineCpus;
       } else {
-        pservers_[i].reset(
+        parameterServers_[i].reset(
             new ParameterServer2(std::string(), config.port() + i));
       }
-      CHECK(pservers_[i]->init()) << "Fail to initialize parameter server"
-                                  << config.port() + i;
+      CHECK(parameterServers_[i]->init()) << "Fail to initialize parameter "
+                                             "server on port "
+                                          << config.port() + i;
     }
   } else {
     str::split(config.nics(), ',', &devices);
-    pservers_.resize(devices.size() * numPorts);
+    parameterServers_.resize(devices.size() * numPorts);
     for (int i = 0; i < numPorts; ++i) {
       for (size_t j = 0; j < devices.size(); ++j) {
         if (config.rdma_tcp() == "rdma") {
-          pservers_[i * devices.size() + j].reset(new ParameterServer2(
+          parameterServers_[i * devices.size() + j].reset(new ParameterServer2(
               getIpAddr(devices[j]), config.port() + i, rdmaCpu++));
           rdmaCpu = rdmaCpu % onlineCpus;
         } else {
-          pservers_[i * devices.size() + j].reset(
+          parameterServers_[i * devices.size() + j].reset(
               new ParameterServer2(getIpAddr(devices[j]), config.port() + i));
         }
-        CHECK(pservers_[i * devices.size() + j]->init())
-            << "Fail to initialize parameter server" << devices[j]
+        CHECK(parameterServers_[i * devices.size() + j]->init())
+            << "Fail to initialize parameter server with device " << devices[j]
             << config.port() + i;
       }
     }
   }
 }
 
-ParameterServerController::~ParameterServerController() { this->join(); }
+ParameterServerController::~ParameterServerController() { this->wait(); }
 
-ParameterServerController* ParameterServerController::createByGflags() {
+ParameterServerController* ParameterServerController::createFromGflags() {
   ParameterServerConfig config;
 
   config.set_nics(FLAGS_nics);
@@ -79,21 +80,21 @@ ParameterServerController* ParameterServerController::create(
 }
 
 void ParameterServerController::start() {
-  LOG(INFO) << "pserver sizes : " << pservers_.size();
+  LOG(INFO) << "number of parameterServer instances: "
+            << parameterServers_.size();
   int i = 0;
-  for (const auto& pserver : pservers_) {
-    LOG(INFO) << "pserver started : " << i;
-    pserver->start();
+  for (const auto& parameterServer : parameterServers_) {
+    LOG(INFO) << "Starting parameterServer[" << i << "]";
+    parameterServer->start();
     i++;
   }
 }
 
-void ParameterServerController::join() {
-  LOG(INFO) << "pserver sizes : " << pservers_.size();
+void ParameterServerController::wait() {
   int i = 0;
-  for (const auto& pserver : pservers_) {
-    LOG(INFO) << "pserver join : " << i;
-    pserver->join();
+  for (const auto& parameterServer : parameterServers_) {
+    LOG(INFO) << "Waiting parameterServer[" << i << "]";
+    parameterServer->join();
     i++;
   }
 }
diff --git a/paddle/pserver/ParameterServerController.h b/paddle/pserver/ParameterServerController.h
index ee249de9d802de141e5848be472b6def513a77d3..fe9bb0b4d02339d0d31d5bc2942932e1f876098b 100644
--- a/paddle/pserver/ParameterServerController.h
+++ b/paddle/pserver/ParameterServerController.h
@@ -21,6 +21,12 @@ limitations under the License. */
 
 namespace paddle {
 
+/**
+ * @brief ParameterServerController is used for create, init and manage multi
+ * parameter server instances. The num of the instances is decided by port
+ * num(the ports number for parameter send) and network devices configured
+ * by gflags or proto.
+ */
 class ParameterServerController final {
 public:
   DISABLE_COPY(ParameterServerController);
@@ -39,28 +45,30 @@ public:
    * @brief create ParameterServerController from gflags, this is used for
    * compatibility with the old usage of configuration by gflags.
    */
-  static ParameterServerController* createByGflags();
+  static ParameterServerController* createFromGflags();
 
   /**
    * @brief create ParameterServerController with ParameterServerConfig, remove
-   * gflags from ParameterServer. Init all pservers thread according to the
-   * config.
+   * gflags from ParameterServer. Init all ParameterServer2 instances according
+   * to
+   * the config.
    */
   static ParameterServerController* create(const ParameterServerConfig& config);
 
   /**
-   * @brief start all pserver thread in this ParameterServerController.
+   * @brief start all ParameterServer2 instances in this
+   * ParameterServerController.
    */
   void start();
 
   /**
-   * @brief join and wait for all pserver thread in this
+   * @brief join and wait for all ParameterServer2 instances thread in this
    * ParameterServerController.
    */
-  void join();
+  void wait();
 
 private:
-  std::vector<std::unique_ptr<ParameterServer2>> pservers_;
+  std::vector<std::unique_ptr<ParameterServer2>> parameterServers_;
 };
 
 }  // namespace paddle
diff --git a/paddle/trainer/TrainerMain.cpp b/paddle/trainer/TrainerMain.cpp
index 61de728f2a2a2830c875bc7adb23031fb33b840a..c5c1d484e5f85c774fd4b8f1d4a8d46abfa2f547 100644
--- a/paddle/trainer/TrainerMain.cpp
+++ b/paddle/trainer/TrainerMain.cpp
@@ -36,10 +36,11 @@ int main(int argc, char** argv) {
   initMain(argc, argv);
   initPython(argc, argv);
 
-  std::unique_ptr<ParameterServerController> pServerPtr(nullptr);
+  std::unique_ptr<ParameterServerController> parameterServerPtr(nullptr);
   if (FLAGS_start_pserver) {
-    pServerPtr.reset(paddle::ParameterServerController::createByGflags());
-    pServerPtr->start();
+    parameterServerPtr.reset(
+        paddle::ParameterServerController::createFromGflags());
+    parameterServerPtr->start();
   }
   Trainer trainer;
   auto config = TrainerConfigHelper::createFromFlags();
diff --git a/proto/ParameterServerConfig.proto b/proto/ParameterServerConfig.proto
index b4fbf901c20cce58a5f1819c05d3518902c4c165..3068bba8b10d89b432b41076dc6eb3ebc40b3883 100644
--- a/proto/ParameterServerConfig.proto
+++ b/proto/ParameterServerConfig.proto
@@ -15,10 +15,17 @@ syntax = "proto2";
 
 package paddle;
 
+
+/**
+ * Configuration structure for ParameterClient2.
+ */
 message ParameterClientConfig {
   required int32 trainer_id = 1;
 }
 
+/**
+ * Configuration structure for ParameterServer2.
+ */
 message ParameterServerConfig {
   // The ports number for parameter send,
   // increment based on default port number