After my test, there is no difference in performance between Netty's NioEventLoopGroup and EpollEventLoopGroup. Why does Netty also provide EpollEventLoopGroup?
When the server maintains 1000 TCP links, there is no difference between CPU and memory of the server. Here is my code:
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;
}
}
}
