How to implement a connection pool with Boost asio? - c++11

Question

I have thousands of concurrent client threads with C10K synchronized request, newing a tcp connect when request comes might be time-consuming, and it cannot be scalable if the number of concurrent threads goes up.
So I thought a shared connection(tcp) pool might be a good choice for me, all connects(tcp) within the pool are activated, all requests share the pool, pull out when need to send message, push in when receiving message done.
But how can I achieve that? By the way, my server side conforms a Mulit-threading Async mode.
The piece code for connection(client-side):
class SyncTCPClient {
public:
SyncTCPClient(const std::string &raw_ip_address, unsigned short port_num) :
m_ep(asio::ip::address::from_string(raw_ip_address), port_num), m_sock(m_ios) {
m_sock.open(m_ep.protocol());
}
void connect() {
m_sock.connect(m_ep);
}
//...
private:
asio::io_service m_ios;
asio::ip::tcp::endpoint m_ep;
asio::ip::tcp::socket m_sock;
};
The piece code for connection pool(client-side):
class ConnectionPool {
private:
std::queue<std::shared_ptr<SyncTCPClient>> pool;
std::mutex mtx;
std::condition_variable no_empty;
public:
ConnectionPool(int size) {
std::cout << "Constructor for connection pool." << std::endl;
for (int i = 0; i < size; i++) {
std::shared_ptr<SyncTCPClient> cliPtr = std::make_shared<SyncTCPClient>(raw_ip_address, port_num);
cliPtr->connect();
pool.push(cliPtr);
}
}
//...
};
The piece code for connection acceptance(server-side):
std::shared_ptr<asio::ip::tcp::socket> sock = std::make_shared<asio::ip::tcp::socket>(m_ios);
m_acceptor.async_accept(*sock.get(),
[this, sock](const boost::system::error_code& error) {
onAccept(error, sock);
}
);
Much appreciated-)