Re: [Boost-users] boost asio synchronous vs asynchronous operations performance

Subject: Re: [Boost-users] boost asio synchronous vs asynchronous operations performance
From: Igor R (boost.lists_at_[hidden])
Date: 2014-03-21 17:39:49

>     void start()
>     {
>         while (socket_.is_open()) {
>             boost::asio::async_write(socket_, boost::asio::buffer(message_),
>                 boost::bind(&tcp_connection::handle_write,
> shared_from_this(),
>                             boost::asio::placeholders::error,
>                             boost::asio::placeholders::bytes_transferred));
>         }
>     }
>
> private:
>     tcp_connection(boost::asio::io_service& io_service)
>         : socket_(io_service),
>           message_(25, 'A')
>     {
>     }
>
>     void handle_write(const boost::system::error_code& error,
>                       size_t bytes_transferred)
>     {
>         if (error) {
>             if (socket_.is_open()) {
>                 std::cout<<"Error while sending data
> asynchronously"<<std::endl;
>                 socket_.close();
>             }
>         }
>     }

I guess in the above handle_wite() you intended to call start() again.

<...>

> When the client is running against synchronous server it is able to receive
> around 700K msgs/sec but when it is running against asynchronous server the
> performance is dropped to around 100K-120K msgs/sec.

Since you use a very small message, the overhead related to the
completion handlers may be significant. In general, it's worth using
performance profiler to see what's going on, but anyway you could use
a trivial "static" handler allocator and see if it helps:
http://www.boost.org/doc/libs/1_55_0/doc/html/boost_asio/example/cpp03/allocation/server.cpp

Of course, ensure you compile with optimizations.