打开IXGBE调试日志发发现：tx使用ixgbe_xmit_pkts_vec，默认tx offload无效了

PMD: ixgbe_set_tx_function(): Using simple tx code path

PMD: ixgbe_set_tx_function(): Vector tx enabled.

PMD: ixgbe_set_tx_function(): Using ixgbe_xmit_pkts_vec

解法：

打开ixgbe_ethdev.c 3113行 修订：

dev_info->default_txconf = (struct rte_eth_txconf) {

    ……

    .txq_flags = 0/*ETH_TXQ_FLAGS_NOMULTSEGS |

            ETH_TXQ_FLAGS_NOOFFLOADS*/,

};

另：

 

/* 修订接口默认配置，如启用TX VLAN OFFLOAD */

struct rte_eth_dev_info dev_info;    

struct rte_eth_txconf *txconf;

rte_eth_dev_info_get (port_id, &dev_info);

txconf = &dev_info.default_txconf;

/* Enable vlan offload */

txconf->txq_flags &= ~ETH_TXQ_FLAGS_NOVLANOFFL;