diff --git a/examples/sudoku/CMakeLists.txt b/examples/sudoku/CMakeLists.txt
index 3967257cd..234d4dd65 100644
--- a/examples/sudoku/CMakeLists.txt
+++ b/examples/sudoku/CMakeLists.txt
@@ -13,6 +13,9 @@ target_link_libraries(sudoku_solver_hybrid muduo_inspect)
 add_executable(sudoku_client_batch batch.cc sudoku.cc)
 target_link_libraries(sudoku_client_batch muduo_net)
 
+add_executable(sudoku_client_pipeline pipeline.cc sudoku.cc)
+target_link_libraries(sudoku_client_pipeline muduo_net)
+
 add_executable(sudoku_loadtest loadtest.cc sudoku.cc)
 target_link_libraries(sudoku_loadtest muduo_net)
 
diff --git a/examples/sudoku/loadtest.cc b/examples/sudoku/loadtest.cc
index f0576ebe0..118c96a30 100644
--- a/examples/sudoku/loadtest.cc
+++ b/examples/sudoku/loadtest.cc
@@ -33,20 +33,19 @@ InputPtr readInput(std::istream& in)
   return input;
 }
 
-typedef boost::function<void(const string&, double)> DoneCallback;
-
 class SudokuClient : boost::noncopyable
 {
  public:
   SudokuClient(EventLoop* loop,
                const InetAddress& serverAddr,
                const InputPtr& input,
-               const string& name)
+               const string& name,
+               bool nodelay)
     : name_(name),
+      tcpNoDelay_(nodelay),
       client_(loop, serverAddr, name_),
       input_(input),
-      count_(0),
-      ticks_(0)
+      count_(0)
   {
     client_.setConnectionCallback(
         boost::bind(&SudokuClient::onConnection, this, _1));
@@ -93,6 +92,8 @@ class SudokuClient : boost::noncopyable
     if (conn->connected())
     {
       LOG_INFO << name_ << " connected";
+      if (tcpNoDelay_)
+        conn->setTcpNoDelay(true);
       conn_ = conn;
     }
     else
@@ -161,12 +162,12 @@ class SudokuClient : boost::noncopyable
   }
 
   const string name_;
+  const bool tcpNoDelay_;
   TcpClient client_;
   TcpConnectionPtr conn_;
   Buffer requests_;
   const InputPtr input_;
   int count_;
-  int ticks_;
   boost::unordered_map<int, Timestamp> sendTime_;
   std::vector<int> latencies_;
 };
@@ -180,7 +181,7 @@ class SudokuLoadtest : boost::noncopyable
   {
   }
 
-  void runClient(const InputPtr& input, const InetAddress& serverAddr, int rps, int conn)
+  void runClient(const InputPtr& input, const InetAddress& serverAddr, int rps, int conn, bool nodelay)
   {
     EventLoop loop;
 
@@ -188,7 +189,7 @@ class SudokuLoadtest : boost::noncopyable
     {
       Fmt f("c%04d", i+1);
       string name(f.data(), f.length());
-      clients_.push_back(new SudokuClient(&loop, serverAddr, input, name));
+      clients_.push_back(new SudokuClient(&loop, serverAddr, input, name, nodelay));
       clients_.back().connect();
     }
 
@@ -271,9 +272,13 @@ int main(int argc, char* argv[])
 {
   int conn = 1;
   int rps = 100;
+  bool nodelay = false;
   InetAddress serverAddr("127.0.0.1", 9981);
   switch (argc)
   {
+    case 6:
+      nodelay = string(argv[5]) == "-n";
+      // FALL THROUGH
     case 5:
       conn = atoi(argv[4]);
       // FALL THROUGH
@@ -286,7 +291,7 @@ int main(int argc, char* argv[])
     case 2:
       break;
     default:
-      printf("Usage: %s input server_ip [requests_per_second] [connections]\n", argv[0]);
+      printf("Usage: %s input server_ip [requests_per_second] [connections] [-n]\n", argv[0]);
       return 0;
   }
 
@@ -296,7 +301,7 @@ int main(int argc, char* argv[])
     InputPtr input(readInput(in));
     printf("%zd requests from %s\n", input->size(), argv[1]);
     SudokuLoadtest test;
-    test.runClient(input, serverAddr, rps, conn);
+    test.runClient(input, serverAddr, rps, conn, nodelay);
   }
   else
   {
diff --git a/examples/sudoku/pipeline.cc b/examples/sudoku/pipeline.cc
new file mode 100644
index 000000000..b2ced9eda
--- /dev/null
+++ b/examples/sudoku/pipeline.cc
@@ -0,0 +1,284 @@
+#include "sudoku.h"
+
+#include <muduo/base/Logging.h>
+#include <muduo/net/EventLoop.h>
+#include <muduo/net/TcpClient.h>
+
+#include <boost/bind.hpp>
+#include <boost/ptr_container/ptr_vector.hpp>
+#include <boost/unordered_map.hpp>
+
+#include <fstream>
+#include <numeric>
+
+#include <stdio.h>
+
+using namespace muduo;
+using namespace muduo::net;
+
+typedef std::vector<string> Input;
+typedef boost::shared_ptr<const Input> InputPtr;
+
+class SudokuClient : boost::noncopyable
+{
+ public:
+  SudokuClient(EventLoop* loop,
+               const InetAddress& serverAddr,
+               const InputPtr& input,
+               const string& name,
+               int pipelines,
+               bool nodelay)
+    : name_(name),
+      pipelines_(pipelines),
+      tcpNoDelay_(nodelay),
+      client_(loop, serverAddr, name_),
+      input_(input),
+      count_(0)
+  {
+    client_.setConnectionCallback(
+        boost::bind(&SudokuClient::onConnection, this, _1));
+    client_.setMessageCallback(
+        boost::bind(&SudokuClient::onMessage, this, _1, _2, _3));
+  }
+
+  void connect()
+  {
+    client_.connect();
+  }
+
+  void report(std::vector<int>* latency, int* infly)
+  {
+    latency->insert(latency->end(), latencies_.begin(), latencies_.end());
+    latencies_.clear();
+    *infly += static_cast<int>(sendTime_.size());
+  }
+
+ private:
+  void onConnection(const TcpConnectionPtr& conn)
+  {
+    if (conn->connected())
+    {
+      LOG_INFO << name_ << " connected";
+      if (tcpNoDelay_)
+        conn->setTcpNoDelay(true);
+      conn_ = conn;
+      send(pipelines_);
+    }
+    else
+    {
+      LOG_INFO << name_ << " disconnected";
+      conn_.reset();
+      // FIXME: exit
+    }
+  }
+
+  void send(int n)
+  {
+    Timestamp now(Timestamp::now());
+    Buffer requests;
+    for (int i = 0; i < n; ++i)
+    {
+      char buf[256];
+      const string& req = (*input_)[count_ % input_->size()];
+      int len = snprintf(buf, sizeof buf, "%s-%08d:%s\r\n",
+                         name_.c_str(), count_, req.c_str());
+      requests.append(buf, len);
+      sendTime_[count_] = now;
+      ++count_;
+    }
+
+    conn_->send(&requests);
+  }
+
+  void onMessage(const TcpConnectionPtr& conn, Buffer* buf, Timestamp recvTime)
+  {
+    size_t len = buf->readableBytes();
+    while (len >= kCells + 2)
+    {
+      const char* crlf = buf->findCRLF();
+      if (crlf)
+      {
+        string response(buf->peek(), crlf);
+        buf->retrieveUntil(crlf + 2);
+        len = buf->readableBytes();
+        if (verify(response, recvTime))
+        {
+          send(1);
+        }
+        else
+        {
+          LOG_ERROR << "Bad response:" << response;
+          conn->shutdown();
+          break;
+        }
+      }
+      else if (len > 100) // id + ":" + kCells + "\r\n"
+      {
+        LOG_ERROR << "Line is too long!";
+        conn->shutdown();
+        break;
+      }
+      else
+      {
+        break;
+      }
+    }
+  }
+
+  bool verify(const string& response, Timestamp recvTime)
+  {
+    size_t colon = response.find(':');
+    if (colon != string::npos)
+    {
+      size_t dash = response.find('-');
+      if (dash != string::npos && dash < colon)
+      {
+        int id = atoi(response.c_str()+dash+1);
+        boost::unordered_map<int, Timestamp>::iterator sendTime = sendTime_.find(id);
+        if (sendTime != sendTime_.end())
+        {
+          int64_t latency_us = recvTime.microSecondsSinceEpoch() - sendTime->second.microSecondsSinceEpoch();
+          latencies_.push_back(static_cast<int>(latency_us));
+          sendTime_.erase(sendTime);
+        }
+        else
+        {
+          LOG_ERROR << "Unknown id " << id << " of " << name_;
+        }
+      }
+    }
+    // FIXME
+    return true;
+  }
+
+  const string name_;
+  const int pipelines_;
+  const bool tcpNoDelay_;
+  TcpClient client_;
+  TcpConnectionPtr conn_;
+  const InputPtr input_;
+  int count_;
+  boost::unordered_map<int, Timestamp> sendTime_;
+  std::vector<int> latencies_;
+};
+
+int getPercentile(const std::vector<int>& latencies, int percent)
+{
+  // The Nearest Rank method
+  assert(latencies.size() > 0);
+  size_t idx = 0;
+  if (percent > 0)
+  {
+    idx = (latencies.size() * percent + 99) / 100 - 1;
+    assert(idx < latencies.size());
+  }
+  return latencies[idx];
+}
+
+void report(boost::ptr_vector<SudokuClient>* clients)
+{
+  std::vector<int> latencies;
+  int infly = 0;
+  for (boost::ptr_vector<SudokuClient>::iterator it = clients->begin();
+       it != clients->end(); ++it)
+  {
+    it->report(&latencies, &infly);
+  }
+
+  LogStream stat;
+  stat << "recv " << Fmt("%6zd", latencies.size()) << " in-fly " << infly;
+
+  if (!latencies.empty())
+  {
+    std::sort(latencies.begin(), latencies.end());
+    int min = latencies.front();
+    int max = latencies.back();
+    int sum = std::accumulate(latencies.begin(), latencies.end(), 0);
+    int mean = sum / static_cast<int>(latencies.size());
+    int median = getPercentile(latencies, 50);
+    int p90 = getPercentile(latencies, 90);
+    int p99 = getPercentile(latencies, 99);
+    stat << " min " << min
+         << " max " << max
+         << " avg " << mean
+         << " median " << median
+         << " p90 " << p90
+         << " p99 " << p99;
+  }
+
+  LOG_INFO << stat.buffer();
+}
+
+InputPtr readInput(std::istream& in)
+{
+  boost::shared_ptr<Input> input(new Input);
+  std::string line;
+  while (getline(in, line))
+  {
+    if (line.size() == implicit_cast<size_t>(kCells))
+    {
+      input->push_back(line.c_str());
+    }
+  }
+  return input;
+}
+
+void runClient(const InputPtr& input,
+               const InetAddress& serverAddr,
+               int conn,
+               int pipelines,
+               bool nodelay)
+{
+  EventLoop loop;
+  boost::ptr_vector<SudokuClient> clients;
+  for (int i = 0; i < conn; ++i)
+  {
+    Fmt f("c%04d", i+1);
+    string name(f.data(), f.length());
+    clients.push_back(new SudokuClient(&loop, serverAddr, input, name, pipelines, nodelay));
+    clients.back().connect();
+  }
+
+  loop.runEvery(1.0, boost::bind(report, &clients));
+  loop.loop();
+}
+
+int main(int argc, char* argv[])
+{
+  int conn = 1;
+  int pipelines = 1;
+  bool nodelay = false;
+  InetAddress serverAddr("127.0.0.1", 9981);
+  switch (argc)
+  {
+    case 6:
+      nodelay = string(argv[5]) == "-n";
+      // FALL THROUGH
+    case 5:
+      pipelines = atoi(argv[4]);
+      // FALL THROUGH
+    case 4:
+      conn = atoi(argv[3]);
+      // FALL THROUGH
+    case 3:
+      serverAddr = InetAddress(argv[2], 9981);
+      // FALL THROUGH
+    case 2:
+      break;
+    default:
+      printf("Usage: %s input server_ip [connections] [pipelines] [-n]\n", argv[0]);
+      return 0;
+  }
+
+  std::ifstream in(argv[1]);
+  if (in)
+  {
+    InputPtr input(readInput(in));
+    printf("%zd requests from %s\n", input->size(), argv[1]);
+    runClient(input, serverAddr, conn, pipelines, nodelay);
+  }
+  else
+  {
+    printf("Cannot open %s\n", argv[1]);
+  }
+}