diff --git a/examples/example.cpp b/examples/example.cpp
index f21a7d638..b8e58f84b 100644
--- a/examples/example.cpp
+++ b/examples/example.cpp
@@ -6,7 +6,7 @@
 class ExampleLogHandler : public crow::ILogHandler {
     public:
         void log(string message, crow::LogLevel level) override {
-            cerr << "ExampleLogHandler -> " << message;
+//            cerr << "ExampleLogHandler -> " << message;
         }
 };
 
@@ -68,7 +68,8 @@ int main()
         return crow::response{os.str()};
     });
 
-    //crow::logger::setLogLevel(LogLevel::INFO);
+    // ignore all log
+    crow::logger::setLogLevel(crow::LogLevel::CRITICAL);
     //crow::logger::setHandler(std::make_shared<ExampleLogHandler>());
 
     app.port(18080)
diff --git a/include/dumb_timer_queue.h b/include/dumb_timer_queue.h
index ebb8bb1bb..86ec7c1f6 100644
--- a/include/dumb_timer_queue.h
+++ b/include/dumb_timer_queue.h
@@ -29,19 +29,17 @@ namespace crow
                 k.first = nullptr;
                 if (!self)
                     return;
-                self->mutex_.lock();
+
                 unsigned int index = (unsigned int)(k.second - self->step_);
                 if (index < self->dq_.size())
                     self->dq_[index].second = nullptr;
-                self->mutex_.unlock();
             }
 
             key add(std::function<void()> f)
             {
-                mutex_.lock();
                 dq_.emplace_back(std::chrono::steady_clock::now(), std::move(f));
                 int ret = step_+dq_.size()-1;
-                mutex_.unlock();
+
                 CROW_LOG_DEBUG << "timer add inside: " << this << ' ' << ret ;
                 return {this, ret};
             }
@@ -50,7 +48,7 @@ namespace crow
             {
                 if (!io_service_)
                     return;
-                mutex_.lock();
+
                 auto now = std::chrono::steady_clock::now();
                 while(!dq_.empty())
                 {
@@ -60,13 +58,12 @@ namespace crow
                     if (x.second)
                     {
                         CROW_LOG_DEBUG << "timer call: " << this << ' ' << step_;
-                        //io_service_->post(std::move(x.second));
+                        // we know that timer handlers are very simple currenty; call here
                         x.second();
                     }
                     dq_.pop_front();
                     step_++;
                 }
-                mutex_.unlock();
             }
 
             void set_io_service(boost::asio::io_service& io_service)
@@ -82,7 +79,6 @@ namespace crow
             int tick{5};
             boost::asio::io_service* io_service_{};
             std::deque<std::pair<decltype(std::chrono::steady_clock::now()), std::function<void()>>> dq_;
-            std::mutex mutex_;
             int step_{};
         };
     }
diff --git a/include/http_connection.h b/include/http_connection.h
index 3232476b5..907485fb6 100644
--- a/include/http_connection.h
+++ b/include/http_connection.h
@@ -26,8 +26,8 @@ namespace crow
     class Connection
     {
     public:
-        Connection(tcp::socket&& socket, Handler* handler, const std::string& server_name) 
-            : socket_(std::move(socket)), 
+        Connection(boost::asio::io_service& io_service, Handler* handler, const std::string& server_name) 
+            : socket_(io_service), 
             handler_(handler), 
             parser_(this), 
             server_name_(server_name)
@@ -48,6 +48,11 @@ namespace crow
 #endif
         }
 
+        tcp::socket& socket()
+        {
+            return socket_;
+        }
+
         void start()
         {
             //auto self = this->shared_from_this();
diff --git a/include/http_server.h b/include/http_server.h
index 73f62f0b2..6dc845aeb 100644
--- a/include/http_server.h
+++ b/include/http_server.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <boost/date_time/posix_time/posix_time.hpp>
 #include <boost/asio.hpp>
 #include <cstdint>
 #include <atomic>
@@ -23,53 +24,80 @@ namespace crow
     public:
         Server(Handler* handler, uint16_t port, uint16_t concurrency = 1)
             : acceptor_(io_service_, tcp::endpoint(asio::ip::address(), port)), 
-            socket_(io_service_), 
             signals_(io_service_, SIGINT, SIGTERM),
             handler_(handler), 
             concurrency_(concurrency),
             port_(port)
         {
-            do_accept();
         }
 
         void run()
         {
+            if (concurrency_ < 0)
+                concurrency_ = 1;
+
+            for(int i = 0; i < concurrency_;  i++)
+                io_service_pool_.emplace_back(new boost::asio::io_service());
+
             std::vector<std::future<void>> v;
             for(uint16_t i = 0; i < concurrency_; i ++)
                 v.push_back(
-                        std::async(std::launch::async, [this]{
+                        std::async(std::launch::async, [this, i]{
                             auto& timer_queue = detail::dumb_timer_queue::get_current_dumb_timer_queue();
-                            timer_queue.set_io_service(io_service_);
-                            while(!io_service_.stopped())
-                            {
+                            timer_queue.set_io_service(*io_service_pool_[i]);
+                            boost::asio::deadline_timer timer(*io_service_pool_[i]);
+                            timer.expires_from_now(boost::posix_time::seconds(1));
+                            std::function<void(const boost::system::error_code& ec)> handler;
+                            handler = [&](const boost::system::error_code& ec){
+                                if (ec)
+                                    return;
                                 timer_queue.process();
-                                io_service_.poll_one();
-                            }
+                                timer.expires_from_now(boost::posix_time::seconds(1));
+                                timer.async_wait(handler);
+                            };
+                            timer.async_wait(handler);
+                            io_service_pool_[i]->run();
                         }));
-
             CROW_LOG_INFO << server_name_ << " server is running, local port " << port_;
 
             signals_.async_wait(
                 [&](const boost::system::error_code& error, int signal_number){
-                    io_service_.stop();
+                    stop();
                 });
-            
+
+            do_accept();
+
+            v.push_back(std::async(std::launch::async, [this]{
+                io_service_.run();
+                CROW_LOG_INFO << "Exiting.";
+            }));
         }
 
         void stop()
         {
             io_service_.stop();
+            for(auto& io_service:io_service_pool_)
+                io_service->stop();
         }
 
     private:
+        asio::io_service& pick_io_service()
+        {
+            // TODO load balancing
+            roundrobin_index_++;
+            if (roundrobin_index_ >= io_service_pool_.size())
+                roundrobin_index_ = 0;
+            return *io_service_pool_[roundrobin_index_];
+        }
+
         void do_accept()
         {
-            acceptor_.async_accept(socket_, 
-                [this](boost::system::error_code ec)
+            auto p = new Connection<Handler>(pick_io_service(), handler_, server_name_);
+            acceptor_.async_accept(p->socket(), 
+                [this, p](boost::system::error_code ec)
                 {
                     if (!ec)
                     {
-                        auto p = new Connection<Handler>(std::move(socket_), handler_, server_name_);
                         p->start();
                     }
                     do_accept();
@@ -78,13 +106,14 @@ namespace crow
 
     private:
         asio::io_service io_service_;
+        std::vector<std::unique_ptr<asio::io_service>> io_service_pool_;
         tcp::acceptor acceptor_;
-        tcp::socket socket_;
         boost::asio::signal_set signals_;
 
         Handler* handler_;
         uint16_t concurrency_{1};
         std::string server_name_ = "Crow/0.1";
         uint16_t port_;
+        unsigned int roundrobin_index_{};
     };
 }