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这篇文章将为大家详细讲解有关 Netty NIO 框架性能压测之如何实现长链接，丸趣 TV 小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。
压测准备
需要将 ulimit -n 改大，否则 nio 链接开不大。
准备 4 台机器 (1 台 netty 服务器，3 台压测机)
使用 apache 的 ab 做压测工具
开始干活
压测代码：
package org.dueam.sample.netty;
package org.dueam.sample.netty;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import java.util.concurrent.Executors;
import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.DynamicChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;
import org.jboss.netty.channel.ChannelHandler.Sharable;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
public class ChatServer {
public static void main(String[] args) throws Exception {if(args.length 1){args = new String[]{ 9876 , true
ChannelFactory factory = new NioServerSocketChannelFactory(Executors
.newCachedThreadPool(), Executors.newCachedThreadPool());
ServerBootstrap bootstrap = new ServerBootstrap(factory);
ChatServerHandler handler = new ChatServerHandler();
ChannelPipeline pipeline = bootstrap.getPipeline();
pipeline.addLast(chat , handler);
bootstrap.setOption(child.tcpNoDelay , true);
bootstrap.setOption(child.keepAlive , true);
int port = Integer.valueOf(args[0]);
bootstrap.bind(new InetSocketAddress(port));
boolean fillChat = true .equals(args[1]);
if (fillChat) {ChannelManagerThread cmt = new ChannelManagerThread();
cmt.start();
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
while (true) {String command = br.readLine();
if (dump .equals(command)) {System.out.println( 当前活着的数量: + channel.size());
} else if (help .equals(command)) {
System.out.println( 命令列表:
System.out.println( dump: 打印当前情况
System.out.println( help: 帮助文档
final static Random random = new Random();
static int max = 0;
static class ChannelManagerThread extends Thread {
@Override
public void run() {while (true) {
try {if(max channel.size()){max = channel.size() ;
System.out.println(live: +channel.size());
for (Channel s : channel.values()) {if (random.nextInt(100) 70) {ChannelBuffer cb = new DynamicChannelBuffer(256);
cb.writeBytes(Hey! 有人来找你了! .getBytes());
s.write(cb);
sleep(500);
} catch (InterruptedException e) {
final static Map Integer, Channel channel = new HashMap Integer, Channel
static void log(String message) {System.out.println(message);
@Sharable
static class ChatServerHandler extends SimpleChannelHandler {
@Override
public void channelConnected(ChannelHandlerContext ctx,
ChannelStateEvent e) {Channel ch = e.getChannel();
ChannelBuffer cb = new DynamicChannelBuffer(256);
cb.writeBytes(Hell! 你来了啊! .getBytes());
ch.write(cb);
channel.put(e.getChannel().getId(), e.getChannel());
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
@Override
public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {e.getCause().printStackTrace();
channel.remove(e.getChannel().getId());
log(remove channel by exception! id: + e.getChannel().getId());
e.getChannel().close();
@Override
public void channelDisconnected(ChannelHandlerContext ctx,
ChannelStateEvent e) throws Exception {channel.remove(e.getChannel().getId());
log(remove channel by exception! id: + e.getChannel().getId());
}压测方式：
# 加大超时和并发量，并使用 keep-alive 的方式保持住端口
./ab -n 20000 -c 20000 -k -t 999999999 -r http://192.168.216.30:9876/压测结果
内存损耗：
[root@cap216030 ~]# free -k -t -s 10
-- 原始内存
total used free shared buffers cached
Mem: 4149076 189828 3959248 0 13196 95484
-/+ buffers/cache: 81148 4067928
Swap: 2096472 208 2096264
Total: 6245548 190036 6055512
-- 执行 chat server 之后
total used free shared buffers cached
Mem: 4149076 207236 3941840 0 13216 96244
-/+ buffers/cache: 97776 4051300
Swap: 2096472 208 2096264
Total: 6245548 207444 6038104
-- 59471 个 nio 连接之后
total used free shared buffers cached
Mem: 4149076 474244 3674832 0 13328 96132
-/+ buffers/cache: 364784 3784292
Swap: 2096472 208 2096264
Total: 6245548 474452 5771096结论：
Netty nio 可以轻松将链接开到 6W，每个线程大概损坏 5k 左右的系统内存
后续压测方案
编写 Java 客户端做内容实时双向推送
使用 100 台机器每台机器起 1000 个线程来模拟客户端进行压测
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