Hi, Stephen Hemminger > -----Original Message----- > From: Zhao1, Wei > Sent: Thursday, November 1, 2018 11:27 AM > To: 'Stephen Hemminger' <step...@networkplumber.org>; Hideyuki > Yamashita <yamashita.hidey...@po.ntt-tx.co.jp> > Cc: dev@dpdk.org > Subject: RE: [dpdk-dev] Question about jumbo frame support on ixgbe > > > > > -----Original Message----- > > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Stephen > Hemminger > > Sent: Wednesday, October 31, 2018 11:49 PM > > To: Hideyuki Yamashita <yamashita.hidey...@po.ntt-tx.co.jp> > > Cc: dev@dpdk.org > > Subject: Re: [dpdk-dev] Question about jumbo frame support on ixgbe > > > > On Wed, 31 Oct 2018 17:22:02 +0900 > > Hideyuki Yamashita <yamashita.hidey...@po.ntt-tx.co.jp> wrote: > > > > > 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? > > > > > > BR, > > > Hideyuki Yamashita > > > NTT TechnoCross > > > > > > > I don't work for Intel, and haven't tried jumbo frames on ixgbe. > > The hardware does support jumbo frames. > > You might be confusing the overlapping receive offload values. > > > > The setting for using jumbo frames is in current DPDK is shown as > > available in device as: > > rx_offload_capa & DEV_RX_OFFLOAD_JUMBO_FRAME In order to > use it, this > > bit must be setn in rx_conf that is passed to rte_eth_rx_queue_setup > > > > Yes, > dev_conf.rxmode.offloads bits of DEV_RX_OFFLOAD_JUMBO_FRAME > should be set to 1 when start port in API rte_eth_dev_start(). > IF you are using testpmd APP, you should set struct rte_eth_rxmode > rx_mode offloads bits of DEV_RX_OFFLOAD_JUMBO_FRAME. > but I think only set this bit of DEV_RX_OFFLOAD_JUMBO_FRAME is not > sufficient for enable this jumbo frame feature, Because in PMD code, this > flag do not set bit of IXGBE_HLREG0_JUMBOEN in register IXGBE_HLREG0, I > think this is something We need update.
Correct some content above, set this bit of DEV_RX_OFFLOAD_JUMBO_FRAME can result in set bit of IXGBE_HLREG0_JUMBOEN in register IXGBE_HLREG0, but it still need some check of packet size boundary for code safe! > > > > > The feature bit that creates multiple mbuf's if necessary on receive is: > > rx_offload_capa & DEV_RX_OFFLOAD_SCATTER Likewise to enable it, > this > > must be set in rte_eth_rx_queue_setup rx_conf. > > > > > > Yes, this step can chose scatter rx function for PMD, but not MUST, details of > discussion for this is in other mail. > https://mails.dpdk.org/archives/dev/2018-November/117771.html After a double check of code, I am sure DEV_RX_OFFLOAD_SCATTER is not a must choice, it is depend on the relationship of max_rx_pkt_len and mbuf size, for example you set max_rx_pkt_len to 9.5k and mbuf size to 2048, of course we need to using scatter receiving mode. > > >
