public void start() throws Exception {
    ServerBootstrap bootstrap = new ServerBootstrap()
        .channel(NioServerSocketChannel.class)
        .group(bossGroup, workerGroup)
        .localAddress(port)
        .option(ChannelOption.SO_BACKLOG, NetUtil.SOMAXCONN)
        .childOption(ChannelOption.SO_KEEPALIVE, true);
    initPipeline(bootstrap, conf);

    Channel ch = bootstrap.bind().sync().channel();
    accepted.add(ch);
    port = ((InetSocketAddress)ch.localAddress()).getPort();
    conf.set(SHUFFLE_PORT_CONFIG_KEY, Integer.toString(port));
    SHUFFLE.setPort(port);
    if (dirWatcher != null) {
      dirWatcher.start();
    }
    LOG.info("LlapShuffleHandler listening on port {} (SOMAXCONN: {})", port, NetUtil.SOMAXCONN);
  }
Should the shuffle use posix_fadvise calls to manage the OS cache during
sendfile
llap-server/src/java/org/apache/hadoop/hive/llap/shufflehandler/ShuffleHandler.java