Poor boost.ASIO performance
I have a very simple server/client performance test using boost::asio on Windows and it seems to be performing really poorly. I'm hoping that I'm just using the library incorrectly and would appreciate any advice.
I have a session class that writes a message-length and then writes a message, and then waits to read a message-length and then read a message, and keeps doing this over and over again nonstop. When I run it locally on my own computer I get blazingly fast performance, however; when I run a server on one computer and a client on another computer, even on the same network, the performance slows down, taking as much as 1 second for a read/write operation to occur.
The server source code file is as follows:
#include <cstdlib>
#include <iostream>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
using namespace boost;
using namespace boost::asio;
using namespace boost::asio::ip;
using namespace std;
class Session {
public:
Session(io_service& ioService)
: m_socket(ioService) {}
tcp::socket& GetSocket() {
return m_socket;
}
void StartRead() {
m_messageSizeIterator = reinterpret_cast<char*>(&m_messageSize);
async_read(m_socket, buffer(m_messageSizeIterator, sizeof(m_messageSize)),
bind(&Session::HandleSizeRead, this, placeholders::error,
placeholders::bytes_transferred));
}
void StartWrite(const char* message, int messageSize) {
m_messageSize = messageSize;
m_message = new char[m_messageSize];
memcpy(m_message, message, m_messageSize);
async_write(m_socket, buffer(&m_messageSize, sizeof(int)),
bind(&Session::HandleSizeWritten, this, placeholders::error));
}
void HandleSizeRead(const system::error_code& error,
size_t bytes_transferred) {
if(!error) {
m_message = new char[m_messageSize];
async_read(m_socket, buffer(m_message, m_messageSize),
bind(&Session::HandleMessageRead, this, placeholders::error,
placeholders::bytes_transferred));
} else {
delete this;
}
}
void HandleMessageRead(const system::error_code& error,
size_t bytes_transferred) {
if(!error) {
cout << string(m_message, m_messageSize) << endl;
async_write(m_socket, buffer(&m_messageSize, sizeof(int)),
bind(&Session::HandleSizeWritten, this, placeholders::error));
} else {
delete this;
}
}
void HandleSizeWritten(const system::error_code& error) {
if(!error) {
async_write(m_socket, buffer(m_message, m_messageSize),
bind(&Session::HandleMessageWritten, this, placeholders::error));
} else {
delete this;
}
}
void HandleMessageWritten(const system::error_code& error) {
if(!error) {
delete m_message;
m_messageSizeIterator = reinterpret_cast<char*>(&m_messageSize);
async_read(m_socket, buffer(m_messageSizeIterator,
sizeof(m_messageSize)), bind(&Session::HandleSizeRead, this,
placeholders::error, placeholders::bytes_transferred));
} else {
delete this;
}
}
private:
tcp::socket m_socket;
int m_messageSize;
char* m_messageSizeIterator;
char* m_message;
};
class Server {
public:
Server(io_service& ioService, short port)
: m_ioService(ioService),
m_acceptor(ioService, tcp::endpoint(tcp::v4(), port)) {
Session* new_session = new Session(m_ioService);
m_acceptor.async_accept(new_session->GetSocket(), bind(&Server::HandleAccept,
this, new_session,asio::placeholders::error));
}
void HandleAccept(Session* new_session, const system::error_code& error) {
if(!error) {
new_session->StartRead();
new_session = new Session(m_ioService);
m_acceptor.async_accept(new_session->GetSocket(), bind(
&Server::HandleAccept, this, new_session, placeholders::error));
} else {
delete new_session;
}
}
private:
io_service& m_ioService;
tcp::acceptor m_acceptor;
};
int main(int argc, char* argv[]) {
try {
if(argc != 2) {
cerr << "Usage: server <port>\n";
return 1;
}
io_service io_service;
Server s(io_service, atoi(argv[1]));
io_service.run();
} catch(std::exception& e) {
cerr << "Exception: " << e.what() << "\n";
}
return 0;
}
And the client code is as follows:
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
using namespace boost;
using namespace boost::asio;
using namespace boost::asio::ip;
using namespace std;
class Session {
public:
Session(io_service& ioService)
: m_socket(ioService) {}
tcp::socket& GetSocket() {
return m_socket;
}
void StartRead() {
m_messageSizeIterator = reinterpret_cast<char*>(&m_messageSize);
async_read(m_socket, buffer(m_messageSizeIterator, sizeof(m_messageSize)),
bind(&Session::HandleSizeRead, this, placeholders::error,
placeholders::bytes_transferred));
}
void StartWrite(const char* message, int messageSize) {
m_messageSize = messageSize;
m_message = new char[m_messageSize];
memcpy(m_message, message, m_messageSize);
async_write(m_socket, buffer(&m_messageSize, sizeof(int)),
bind(&Session::HandleSizeWritten, this, placeholders::error));
}
void HandleSizeRead(const system::error_code& error,
size_t bytes_transferred) {
if(!error) {
m_message = new char[m_messageSize];
async_read(m_socket, buffer(m_message, m_messageSize),
bind(&Session::HandleMessageRead, this, placeholders::error,
placeholders::bytes_transferred));
} else {
delete this;
}
}
void HandleMessageRead(const system::error_code& error,
size_t bytes_transferred) {
if(!error) {
cout << string(m_message, m_messageSize) << endl;
async_write(m_socket, buffer(&m_messageSize, sizeof(int)),
bind(&Session::HandleSizeWritten, this, placeholders::error));
} else {
delete this;
}
}
void HandleSizeWritten(const system::error_code& error) {
if(!error) {
async_write(m_socket, buffer(m_message, m_messageSize),
bind(&Session::HandleMessageWritten, this, placeholders::error));
} else {
delete this;
}
}
void HandleMessageWritten(const system::error_code& error) {
if(!error) {
delete m_message;
m_messageSizeIterator = reinterpret_cast<char*>(&m_messageSize);
async_read(m_socket, buffer(m_messageSizeIterator,
sizeof(m_messageSize)), bind(&Session::HandleSizeRead, this,
placeholders::error, placeholders::bytes_transferred));
} else {
delete this;
}
}
private:
tcp::socket m_socket;
int m_messageSize;
char* m_messageSizeIterator;
char* m_message;
};
int main(int argc, char* argv[]) {
try {
if(argc != 3) {
cerr << "Usage: client <host> <port>\n";
return 1;
}
io_service io_service;
tcp::resolver resolver(io_service);
tcp::resolver::query query(tcp::v4(), argv[1], argv[2]);
tcp::resolver::iterator iterator = resolver.resolve(query);
Session session(io_service);
tcp::socket& s = session.GetSocket();
s.connect(*iterator);
cout << "Enter message: ";
const int MAX_LENGTH = 1024;
char request[MAX_LENGTH];
cin.getline(request, MAX_LENGTH);
int requestLength = strlen(request);
session.StartWrite(request, requestLength);
io_service.run();
} catch (std::exception& e) {
cerr << "Exception: " << e.what() << "\n";
}
return 0;
}
Any help would be appreciated, thanks.
For my purposes, sending really really small messages and wanting virtual real time replies, disabling Nagle's algorithm turned out to be the cause of the poor performance.
Answer
You must turn off the Nagle algorithm. Call:
m_socket.set_option(tcp::no_delay(true));
Where appropriate for your code.