c++ boost::asio
connect=10000,active connect=100,req=148791,time=60,req/sec=2479.85,msec/req=40.343

erlang kernel-poll false
connect=10000,active connect=100,req=979803,time=60,req/sec=16330,msec/req=6.12356

node.js
connect=10000,active connect=100,req=1378370,time=60,req/sec=22972.8,msec/req=4.35543

c libevent
connect=10000,active connect=100,req=3719106,time=60,req/sec=61985.1,msec/req=1.61258

erlang kernel-poll true
connect=10000,active connect=100,req=6377574,time=60,req/sec=106293,msec/req=0.939882

看到這個資料,立馬嚇尿了. 見過黑C++,黑Boost的,沒見過黑這麼狠的.這資料簡直是要顛覆我的世界觀啊!!!

沒有辦法,為了查明真相,只能自己寫個程式測試一下. 原帖子裡面包含了一個asio的echo_server, 稍微看了一下,程式碼沒多大問題,就是delete this有點刺眼, 於是順便改了一下程式.

// echo_server.cpp// g++ -o echo_server -O3 echo_server.cpp -lboost_system -lboost_thread
 
#include <cstdlib>#include <iostream>#include <boost/bind.hpp>#include <boost/asio.hpp>#include <boost/thread/thread.hpp>#include <boost/shared_ptr.hpp>#include <boost/enable_shared_from_this.hpp>using boost::asio::ip::tcp;int total_conn = 0;class session : public boost::enable_shared_from_this<session>{public
 
:  session(boost::asio::io_service& io_service)    : socket_(io_service)  {  }  tcp::socket& socket()  {    return socket_;  }  void start()  {    socket_.async_read_some(boost::asio::buffer(data_, max_length),        boost::bind(&session::handle_read, shared_from_this(),          boost::asio::placeholders::error,          boost::asio::placeholders::bytes_transferred));  }private:  void handle_read(const boost::system::error_code& error,      size_t bytes_transferred)  {    if (!error)    {      boost::asio::async_write(socket_,          boost::asio::buffer(data_, bytes_transferred),          boost::bind(&session::handle_write, shared_from_this(),            boost::asio::placeholders::error));    }  }  void handle_write(const boost::system::error_code& error)  {    if (!error)    {      socket_.async_read_some(boost::asio::buffer(data_, max_length),          boost::bind(&session::handle_read, shared_from_this(),            boost::asio::placeholders::error,            boost::asio::placeholders::bytes_transferred));    }  }  tcp::socket socket_;  enum { max_length = 1024 };  char data_[max_length];};class server{public:  server(boost::asio::io_service& io_service, short port)    : io_service_(io_service),      acceptor_(io_service, tcp::endpoint(tcp::v4(), port))  {    start_accept();  }private:  void start_accept()  {   boost::shared_ptr<session> new_session(new session(io_service_));    acceptor_.async_accept(new_session->socket(),        boost::bind(&server::handle_accept, this, new_session,          boost::asio::placeholders::error));  }  void handle_accept(boost::shared_ptr<session> new_session,      const boost::system::error_code& error)  {    start_accept();    if (!error)    {      std::cout << "total connect =" << ++total_conn <<std::endl;      new_session->start();    }  }  boost::asio::io_service& io_service_;  tcp::acceptor acceptor_;};int main(int argc, char* argv[]){  try  {    if (argc < 2)    {      std::cerr << "Usage: async_tcp_echo_server <port>\n";      return 1;    }    boost::asio::io_service io_service;    using namespace std; // For atoi.    server s(io_service, atoi(argv[1]));    int thread_num = 6;    if (argc > 2)   thread_num = atoi(argv[2]);    boost::thread_group th_group;     for (int i=0; i<thread_num; ++i)    {   th_group.add_thread(new boost::thread(boost::bind(&boost::asio::io_service::run, &io_service)));    }    th_group.join_all();  }  catch (std::exception& e)  {    std::cerr << "Exception: " << e.what() << "\n";  }  return 0;}

然後把nodejs, erlang, libevent都拿來對比一下(nodejs還真是簡潔)

/// echo_server.jsvar net = require("net");var server = net.createServer(function(req) {    req.on('data', function(data) {        req.write(data);    });});server.listen(8000);

下面是erlang的

-module(echo_server).-export([start/0]).start() ->        {ok, Listen} = gen_tcp:listen(9000, [binary,                                                %{packet, 4},                                                {reuseaddr, true},                                                {backlog, 2000},                                                {active, true}]),        spawn(fun() -> par_connect(Listen, 0) end).par_connect(Listen, Count) ->        {ok, Socket} = gen_tcp:accept(Listen),        New = Count + 1,        io:format("Accept succ ~p~n", [New]),        spawn(fun() -> par_connect(Listen, New) end),        loop(Socket).loop(Socket) ->    receive        {tcp, Socket, Bin} ->            gen_tcp:send(Socket, Bin),            loop(Socket);        {tcp_closed, Socket} ->            io:format("Server socket closed~n")    end.

下面是libevent版本

#include <stdlib.h>#include <unistd.h>#include <netinet/in.h>  #include <sys/socket.h>  #include <sys/types.h>  #include <sys/socket.h>#include <event.h>  #include <stdio.h>  #include <time.h> #include <string.h>#include <fcntl.h>int buf_len = 8192;int msg_len = 4096; int total = 0;int setnonblock(int fd){        int flags;        flags = fcntl(fd, F_GETFL);        if (flags < 0)                 return flags;        flags |= O_NONBLOCK;        if (fcntl(fd, F_SETFL, flags) < 0)                 return -1;        return 0;}void connection_echo(int fd, shortevent, void *arg){ structevent *ev = (structevent *)arg; event_add(ev, NULL); char buf[buf_len]; int read_len = read(fd, buf, msg_len); write(fd, buf, read_len);}void connection_accept(int fd, shortevent, void *arg)   {     /* for debugging */  //fprintf(stderr, "%s(): fd = %d, event = %d, total = %d.\n", __func__, fd, event, ++total);      /* Accept a new connection. */     struct sockaddr_in s_in;      socklen_t len = sizeof(s_in);      int ns = accept(fd, (struct sockaddr *) &s_in, &len);      if (ns < 0) {          perror("accept");          return;      }   setnonblock(ns);    /* Install echo server. */     structevent *ev = (structevent *)malloc(sizeof(structevent));      event_set(ev, ns, EV_READ, connection_echo, ev);      event_add(ev, NULL);  } int main(void)  {      /* Request socket. */     int s = socket(PF_INET, SOCK_STREAM, 0);      if (s < 0) {          perror("socket");          exit(1);      }      /* bind() */     struct sockaddr_in s_in;      memset(&s_in, 0, sizeof(s_in));      s_in.sin_family = AF_INET;      s_in.sin_port = htons(9000);      s_in.sin_addr.s_addr = INADDR_ANY;      if (bind(s, (struct sockaddr *) &s_in, sizeof(s_in)) < 0) {          perror("bind");          exit(1);      }      /* listen() */     if (listen(s, 1000) < 0) {          perror("listen");          exit(1);      }      /* Initial libevent. */     event_init();      /* Create event. */     structevent ev;      event_set(&ev, s, EV_READ | EV_PERSIST, connection_accept, &ev);      /* Add event. */     event_add(&ev, NULL);      event_dispatch();      return 0;  } 

最後是測試程式,用我們最愛的asio寫的, 發起10000的非同步連線, 連線成功後寫入"hello world",然後等待返回,返回後就斷開連線

// echo_client.cpp// g++ -o echo_client -O3 echo_client.cpp -lboost_system -lboost_thread#include <boost/asio.hpp>namespace asio = boost::asio;using asio::ip::tcp;#include <boost/bind.hpp>#include <boost/shared_ptr.hpp>#include <boost/enable_shared_from_this.hpp>class session  : public boost::enable_shared_from_this<session>{public: session(asio::io_service& io)  : socket_(io) { } tcp::socket& socket() { return socket_; } void start() {  asio::async_write(socket_, asio::buffer(output_buffer_, 12), boost::bind(&session::handle_write, shared_from_this(), _1, _2)); } void handle_write(const boost::system::error_code& ec, std::size_t bytes_transfered) {  if(!ec)   {   asio::async_read(socket_, asio::buffer(input_buffer_, 12), boost::bind(&session::handle_read, shared_from_this(), _1, _2));  } else {   std::cerr << "write error:" << ec.message() << std:: endl;  } } void handle_read(const boost::system::error_code& ec, std::size_t bytes_transfered) {  if(ec)  {   std::cerr << "read error:" << ec.message() << std::endl;  } }private: tcp::socket socket_; char output_buffer_[12]; char input_buffer_[12];};void handle_connect(boost::shared_ptr<session> session_ptr, const boost::system::error_code& ec){ if(ec)  {  std::cerr << "connect error:" << ec.message() << std::endl; } else {  session_ptr->start(); }}int main(int argc, char* argv[]){ asio::io_service io; tcp::resolver resolver(io); tcp::resolver::iterator endpoint = resolver.resolve(tcp::resolver::query("localhost", argv[1])); boost::shared_ptr<session> session_ptr; for(int i = 0; i < 10000; i++) {  session_ptr.reset(new session(io));  asio::async_connect(session_ptr->socket(), endpoint, boost::bind(handle_connect, session_ptr, _1)); } io.run();}

我首先測試了一下c++版本, 結果悲劇了,開2000個連線,居然要3s?

但是靠著堅定的asio/C++信仰, 仔細想了一想原因, 接著看了一下伺服器日誌,發現伺服器連線數大概在1000多. 差不多每次都是這麼多. 估計是ulimit的限制, 使用ulimit -n 99999放開伺服器和客戶端的限制. 果然,處理10000連線只需0.7秒.

c++測試結果:

localhost test # time ./echo_client 8000real    0m0.798suser    0m0.169ssys     0m0.626slocalhost test # time ./echo_client 8000real    0m0.843suser    0m0.132ssys     0m0.707slocalhost test # time ./echo_client 8000real    0m0.762suser    0m0.161ssys     0m0.598slocalhost test # time ./echo_client 8000real    0m0.774suser    0m0.145ssys     0m0.628s

但是測試過程中碰到了另一個問題,就是重複測試的時候,會在連線時出現 Cannot assign requested address 錯誤. 經過網上查詢資料, 是可用埠被用光了,系統還沒來得及回收.使用如下命令開啟埠tw_reuse

echo "1" > /proc/sys/net/ipv4/tcp_tw_reuse

這些測試就ok了,每次都在0.7秒左右.

接下來測試 nodejs

nodejs測試結果:

localhost test # time ./echo_client 8000real    0m3.193suser    0m0.140ssys     0m0.484slocalhost test # time ./echo_client 8000real    0m0.729suser    0m0.144ssys     0m0.494slocalhost test # time ./echo_client 8000real    0m3.176suser    0m0.141ssys     0m0.489slocalhost test # time ./echo_client 8000real    0m3.727suser    0m0.136ssys     0m0.489s

下面是libevent的結果, 效率挺不錯的, 比asio快了10%左右(有人想問,為什麼只有一次測試? 那是因為server掛掉了, 我不是很懂c, 不知道記憶體洩露出在哪裡)

localhost test # time ./echo_client 9000real    0m0.643suser    0m0.130ssys     0m0.512s

最後是那位作者力挺的erlang, 
還好我看過幾天erlang,要不然我都不知道程式是怎麼執行的
erl +K true 啟用kernel-poll進入shell,c(echo_server). 編譯echo_server程式.echo_server:start(). 開啟伺服器

/// 前面還有好多好多reset..... read error:Connection reset by peerread error:Connection reset by peerreal    0m13.207suser    0m0.168ssys     0m0.418s

結果就是這個結果, 要是不信的話可以自己去試試.