diff --git a/CMakeLists.txt b/CMakeLists.txt
index fcb8103ec..2e432baa2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,6 +50,7 @@ find_path(MHD_INCLUDE_DIR microhttpd.h)
 find_library(MHD_LIBRARY NAMES microhttpd)
 find_library(BOOSTTEST_LIBRARY NAMES boost_unit_test_framework)
 find_library(BOOSTPO_LIBRARY NAMES boost_program_options)
+find_library(BOOSTSYSTEM_LIBRARY NAMES boost_system)
 find_path(TCMALLOC_INCLUDE_DIR gperftools/heap-profiler.h)
 find_library(TCMALLOC_LIBRARY NAMES tcmalloc_and_profiler)
 find_path(HIREDIS_INCLUDE_DIR hiredis/hiredis.h)
diff --git a/examples/ace/ttcp/CMakeLists.txt b/examples/ace/ttcp/CMakeLists.txt
index 1b4834bbb..028c967de 100644
--- a/examples/ace/ttcp/CMakeLists.txt
+++ b/examples/ace/ttcp/CMakeLists.txt
@@ -1,4 +1,3 @@
-
 if(BOOSTPO_LIBRARY)
   add_executable(ttcp_blocking ttcp_blocking.cc common.cc main.cc)
   target_link_libraries(ttcp_blocking muduo_base boost_program_options)
@@ -6,6 +5,13 @@ if(BOOSTPO_LIBRARY)
 
   add_executable(ttcp_muduo ttcp.cc common.cc main.cc)
   target_link_libraries(ttcp_muduo muduo_net boost_program_options)
-  set_target_properties(ttcp_muduo PROPERTIES COMPILE_FLAGS "-Wno-error=conversion")
+
+  if(BOOSTSYSTEM_LIBRARY)
+    add_executable(ttcp_asio_sync ttcp_asio_sync.cc common.cc main.cc)
+    target_link_libraries(ttcp_asio_sync muduo_base boost_program_options boost_system)
+
+    add_executable(ttcp_asio_async ttcp_asio_async.cc common.cc main.cc)
+    target_link_libraries(ttcp_asio_async muduo_base boost_program_options boost_system)
+  endif()
 endif()
 
diff --git a/examples/ace/ttcp/ttcp_asio_async.cc b/examples/ace/ttcp/ttcp_asio_async.cc
new file mode 100644
index 000000000..ab1168191
--- /dev/null
+++ b/examples/ace/ttcp/ttcp_asio_async.cc
@@ -0,0 +1,173 @@
+#include <examples/ace/ttcp/common.h>
+
+#include <muduo/base/Logging.h>
+#include <boost/asio.hpp>
+#include <boost/bind.hpp>
+#include <boost/enable_shared_from_this.hpp>
+#include <stdio.h>
+
+using boost::asio::ip::tcp;
+
+void transmit(const Options& opt)
+{
+  try
+  {
+  }
+  catch (std::exception& e)
+  {
+    LOG_ERROR << e.what();
+  }
+}
+
+class TtcpServerConnection : boost::noncopyable,
+  public boost::enable_shared_from_this<TtcpServerConnection>
+{
+ public:
+  TtcpServerConnection(boost::asio::io_service& io_service)
+    : socket_(io_service), count_(0), payload_(NULL), ack_(0)
+  {
+    sessionMessage_.number = 0;
+    sessionMessage_.length = 0;
+  }
+
+  ~TtcpServerConnection()
+  {
+    ::free(payload_);
+  }
+
+  tcp::socket& socket() { return socket_; }
+
+  void start()
+  {
+    std::ostringstream oss;
+    oss << socket_.remote_endpoint();
+    LOG_INFO << "Got connection from " << oss.str();
+    boost::asio::async_read(
+        socket_, boost::asio::buffer(&sessionMessage_, sizeof(sessionMessage_)),
+        boost::bind(&TtcpServerConnection::handleReadSession, shared_from_this(),
+                    boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
+  }
+
+ private:
+  void handleReadSession(const boost::system::error_code& error, size_t len)
+  {
+    if (!error && len == sizeof sessionMessage_)
+    {
+      sessionMessage_.number = ntohl(sessionMessage_.number);
+      sessionMessage_.length = ntohl(sessionMessage_.length);
+      printf("receive number = %d\nreceive length = %d\n",
+             sessionMessage_.number, sessionMessage_.length);
+      const int total_len = static_cast<int>(sizeof(int32_t) + sessionMessage_.length);
+      payload_ = static_cast<PayloadMessage*>(::malloc(total_len));
+      payload_->length = 0;
+      boost::asio::async_read(
+          socket_, boost::asio::buffer(&payload_->length, sizeof payload_->length),
+          boost::bind(&TtcpServerConnection::handleReadLength, shared_from_this(),
+                      boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
+    }
+    else
+    {
+      LOG_ERROR << "read session message: " << error.message();
+    }
+  }
+
+  void handleReadLength(const boost::system::error_code& error, size_t len)
+  {
+    if (!error && len == sizeof payload_->length)
+    {
+      payload_->length = ntohl(payload_->length);
+      assert(payload_->length == sessionMessage_.length);
+      boost::asio::async_read(
+          socket_, boost::asio::buffer(&payload_->data, payload_->length),
+          boost::bind(&TtcpServerConnection::handleReadPayload, shared_from_this(),
+                      boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
+    }
+    else
+    {
+      LOG_ERROR << "read length: " << error.message();
+    }
+  }
+
+  void handleReadPayload(const boost::system::error_code& error, size_t len)
+  {
+    if (!error && len == static_cast<size_t>(payload_->length))
+    {
+      ack_ = htonl(payload_->length);
+      boost::asio::async_write(
+          socket_, boost::asio::buffer(&ack_, sizeof ack_),
+          boost::bind(&TtcpServerConnection::handleWriteAck, shared_from_this(),
+                      boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
+    }
+    else
+    {
+      LOG_ERROR << "read payload data: " << error.message();
+    }
+  }
+
+  void handleWriteAck(const boost::system::error_code& error, size_t len)
+  {
+    if (!error && len == sizeof ack_)
+    {
+      if (++count_ < sessionMessage_.number)
+      {
+        payload_->length = 0;
+        boost::asio::async_read(
+            socket_, boost::asio::buffer(&payload_->length, sizeof payload_->length),
+            boost::bind(&TtcpServerConnection::handleReadLength, shared_from_this(),
+                        boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
+      }
+      else
+      {
+        LOG_INFO << "Done";
+      }
+    }
+    else
+    {
+      LOG_ERROR << "write ack: " << error.message();
+    }
+  }
+
+  tcp::socket socket_;
+  int count_;
+  struct SessionMessage sessionMessage_;
+  struct PayloadMessage* payload_;
+  int32_t ack_;
+};
+typedef boost::shared_ptr<TtcpServerConnection> TtcpServerConnectionPtr;
+
+void startAccept(tcp::acceptor& acceptor);
+
+void handleAccept(tcp::acceptor& acceptor, TtcpServerConnectionPtr new_connection,
+                  const boost::system::error_code& error)
+{
+  if (!error)
+  {
+    new_connection->start();
+  }
+
+  startAccept(acceptor);
+}
+
+void startAccept(tcp::acceptor& acceptor)
+{
+  TtcpServerConnectionPtr new_connection(new TtcpServerConnection(acceptor.get_io_service()));
+  acceptor.async_accept(new_connection->socket(),
+                         boost::bind(handleAccept, boost::ref(acceptor), new_connection,
+                                     boost::asio::placeholders::error));
+}
+
+void receive(const Options& opt)
+{
+  try
+  {
+    boost::asio::io_service io_service;
+    tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4(), opt.port));
+    startAccept(acceptor);
+    io_service.run();
+  }
+  catch (std::exception& e)
+  {
+    LOG_ERROR << e.what();
+  }
+}
+
diff --git a/examples/ace/ttcp/ttcp_asio_sync.cc b/examples/ace/ttcp/ttcp_asio_sync.cc
new file mode 100644
index 000000000..1bad4b121
--- /dev/null
+++ b/examples/ace/ttcp/ttcp_asio_sync.cc
@@ -0,0 +1,75 @@
+#include <examples/ace/ttcp/common.h>
+
+#include <muduo/base/Logging.h>
+#include <boost/asio.hpp>
+#include <stdio.h>
+
+using boost::asio::ip::tcp;
+
+void transmit(const Options& opt)
+{
+  try
+  {
+  }
+  catch (std::exception& e)
+  {
+    LOG_ERROR << e.what();
+  }
+}
+
+void receive(const Options& opt)
+{
+  try
+  {
+    boost::asio::io_service io_service;
+    tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4(), opt.port));
+    tcp::socket socket(io_service);
+    acceptor.accept(socket);
+
+    struct SessionMessage sessionMessage = { 0, 0 };
+    boost::system::error_code error;
+    size_t nr = boost::asio::read(socket, boost::asio::buffer(&sessionMessage, sizeof sessionMessage), error);
+    if (nr != sizeof sessionMessage)
+    {
+      LOG_ERROR << "read session message: " << error.message();
+      exit(1);
+    }
+
+    sessionMessage.number = ntohl(sessionMessage.number);
+    sessionMessage.length = ntohl(sessionMessage.length);
+    printf("receive number = %d\nreceive length = %d\n",
+           sessionMessage.number, sessionMessage.length);
+    const int total_len = static_cast<int>(sizeof(int32_t) + sessionMessage.length);
+    PayloadMessage* payload = static_cast<PayloadMessage*>(::malloc(total_len));
+    // std::unique_ptr<PayloadMessage, void (*)(void*)> freeIt(payload, ::free);
+    boost::shared_ptr<PayloadMessage> freeIt(payload, ::free);
+    assert(payload);
+
+    for (int i = 0; i < sessionMessage.number; ++i)
+    {
+      payload->length = 0;
+      if (boost::asio::read(socket, boost::asio::buffer(&payload->length, sizeof(payload->length)), error) != sizeof(payload->length))
+      {
+        LOG_ERROR << "read length: " << error.message();
+        exit(1);
+      }
+      payload->length = ntohl(payload->length);
+      assert(payload->length == sessionMessage.length);
+      if (boost::asio::read(socket, boost::asio::buffer(payload->data, payload->length), error) != static_cast<size_t>(payload->length))
+      {
+        LOG_ERROR << "read payload data: " << error.message();
+        exit(1);
+      }
+      int32_t ack = htonl(payload->length);
+      if (boost::asio::write(socket, boost::asio::buffer(&ack, sizeof(ack))) != sizeof(ack))
+      {
+        LOG_ERROR << "write ack: " << error.message();
+        exit(1);
+      }
+    }
+  }
+  catch (std::exception& e)
+  {
+    LOG_ERROR << e.what();
+  }
+}
diff --git a/examples/procmon/procmon.cc b/examples/procmon/procmon.cc
index e16b1eb3f..b930aa0a5 100644
--- a/examples/procmon/procmon.cc
+++ b/examples/procmon/procmon.cc
@@ -90,7 +90,7 @@ class Procmon : boost::noncopyable
       kBootTime_(getBootTime()),
       pid_(pid),
       server_(loop, InetAddress(port), getName()),
-      procname_(ProcessInfo::procname(readProcFile("stat")).as_string()),
+      procname_(procname ? procname : ProcessInfo::procname(readProcFile("stat")).as_string()),
       hostname_(ProcessInfo::hostname()),
       cmdline_(getCmdLine()),
       ticks_(0),
@@ -462,7 +462,7 @@ int main(int argc, char* argv[])
 
   EventLoop loop;
   uint16_t port = static_cast<uint16_t>(atoi(argv[2]));
-  Procmon procmon(&loop, pid, port, argc > 3 ? argv[3] : "");
+  Procmon procmon(&loop, pid, port, argc > 3 ? argv[3] : NULL);
   procmon.start();
   loop.loop();
 }