经过我的测试，Netty的NioEventLoopGroup和EpollEventLoopGroup在性能上没有区别。那么为什么Netty还提供EpollEventLoopGroup呢？
当服务器维护1000个TCP连接时，服务器的CPU和内存之间没有区别。以下是我的代码：
public class EpollServer {
public static void main(String[] args) throws Exception {
logger.info("port:"+System.getProperty("port", "8007"));
logger.info("isUseEpoll:"+System.getProperty("isUserEpoll","true"));
EventLoopGroup bossGroup;
EventLoopGroup workerGroup;
Class clazz;
if (useEpoll()) {
bossGroup = new EpollEventLoopGroup(1);
workerGroup = new EpollEventLoopGroup();
clazz = EpollServerSocketChannel.class;
}else{
bossGroup = new NioEventLoopGroup(1);
workerGroup = new NioEventLoopGroup();
clazz = NioServerSocketChannel.class;
}
final EpollServerHandler epollHandler = new EpollServerHandler();
try {
ServerBootstrap b = new ServerBootstrap();
logger.info("[socket Type]: {}", clazz.getSimpleName());
b.group(bossGroup, workerGroup)
.channel(clazz)
.option(ChannelOption.SO_BACKLOG, 10001)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline p = ch.pipeline();
p.addLast(new LengthFieldBasedFrameDecoder(1024,0,2,0,2));
p.addLast(new SimpleChannelInboundHandler(){
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf content = (ByteBuf) msg;
ctx.channel().writeAndFlush(content.retain());
}
});
}
});
ChannelFuture f = b.bind(PORT).sync();
f.channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
private static boolean useEpoll() {
if(isUseEpoll){
return Epoll.isAvailable();
}else{
return false;
}
}
}