Hi Thanks for your answering to my question. Please see inline. > 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. Thanks for your info.
> 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! What will happen if DEV_TX_OFFLOAD_MULTI_SEGS is set to 1. Packets are sent fragmented or re-built as a Jumbo frame and sent to network? (My guess is former(packet will be sent fragmented though)) > 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. I want to know the relationship between 1,2 and 3. Do I have to do all 3 steps to send/receive jumbo frame? Or, when I relalize jumbo frame support programatically execute 1 and 2, if I do not modify program and just change setting via CLI then execute 3? Thanks and BR, Hideyuki Yamashita NTT TechnoCross > 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 >
