Hi, Hideyuki Yamashita
> -----Original Message----- > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Hideyuki Yamashita > Sent: Wednesday, October 31, 2018 4:22 PM > To: dev@dpdk.org > Subject: [dpdk-dev] Question about jumbo frame support on ixgbe > > Hi, > > I have a very basic question about jumbo frame support for ixgbe. > > I understand that some drivers support jumbo frame and if it receive jumbo > packet (greater than 1500 byte), it creates mbuf chains and pass it to DPDK > application through e.g. rte_eth_rx_burst. > > However it looks that ixgbe driver does not support jumbo frame. > > Q1. Is my understanding above correct? > Q2. If A1 equals YES, then are there any future plan to support jumbo frame > on ixgbe? Your understanding above correct, but 82599 and x550 has support jumbo frame receive by now! In order to use this feature on ixgbe, you need do the following steps: 1. you must set dev_conf.rxmode. max_rx_pkt_len to a big number, eg. 9500, when doing port start, for example when start port in API rte_eth_dev_start(). ixgbe_dev_rx_init() will chose a scatter receive function if the max_rx_pkt_len is larger than the mbuf size, you do not need to set DEV_RX_OFFLOAD_SCATTER bit in dev_conf.rxmode.offloads, this is the work of PMD driver when it detect jumbo frame is needed to be supported. 2. set dev_conf.txmode.offloads bit of DEV_TX_OFFLOAD_MULTI_SEGS to 1 when doing rte_eth_tx_queue_setup() or , this is very important!! If you not do this, you may only receive JUMBO frame but not forward out. Because as you say, the receive packets maybe has a mbuf chains(depending on the size relationship of mbuf size and the max_rx_pkt_len). But in ixgbe PMD for setting tx function, it is confusing in ixgbe_set_tx_function(), you need to take care of it, it is based on queue offloads bit! 3. enable it using CLI "port config mtu <port_id> <value>" if you are using testpmd or using API rte_eth_dev_set_mtu() for your own APP. The mtu number is just what you need to update for a large number. And all my discussion is based on pf port, if you are using vf, we can have a further discussion. Please feel free to contact me if necessary. > > BR, > Hideyuki Yamashita > NTT TechnoCross
