Hi Asim,
> -----Original Message----- > From: Asim Jamshed [mailto:asim.jamshed at gmail.com] > Sent: Tuesday, June 28, 2016 5:23 PM > To: Lu, Wenzhuo > Cc: dev at dpdk.org > Subject: Re: [dpdk-dev] Fwd: dpdk ixgbe PMD lro limits > > On Tue, Jun 28, 2016 at 5:42 PM, Lu, Wenzhuo <wenzhuo.lu at intel.com> wrote: > > Hi Asim, > > > > > >> -----Original Message----- > >> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Asim Jamshed > >> Sent: Tuesday, June 28, 2016 2:41 PM > >> To: dev at dpdk.org > >> Subject: [dpdk-dev] Fwd: dpdk ixgbe PMD lro limits > >> > >> Hi, > >> > >> Apologies in advance if this question has been asked in the past. > >> > >> I have been performing mTCP-related tests on dpdk-16.04 with ixgbe > >> PMD. I am using 82599ES 10-Gigabit adapters for my experiments. I > >> have a few queries regarding LRO. > >> > >> 1) What is the theoretical maximum size of the Ethernet frame I can > >> get from the driver once LRO is enabled? In my experiments, I was > >> seeing packet size as high as 16KB. Can it be as high as ~2^16 bytes (iph- > >tot_len)? > > I'm not sure about if I understand your question correctly. Assume you're > talking about the TCP segment after LRO. So, it's said there are no > limitations on > the maximum packet length. > > The issue that I am facing is fixing the size of mbuf. > The default size of mbuf is (2048 + sizeof(struct rte_mbuf) + > RTE_PKTMBUF_HEADROOM) which needs to be augmented once lro is enabled > (am I right?). I tried stretching the limits of the mempool by increasing > mbuf size > to (65536 + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM), and I got the > following error: I don't think you need to change the size of mbuf. Please check this field of mbuf, "struct rte_mbuf *next; /**< Next segment of scattered packet. */" > > Initializing port 0... EAL: Error - exiting with code: 1 > Cause: rte_eth_rx_queue_setup:err=-22, port=0, queueid: 0 > > My exact calls for rte_mempool_create() and > rte_eth_rx_queue_setup() were: > > pktmbuf_pool = rte_mempool_create(name, 8192, > MBUF_SIZE, 256, > sizeof(struct rte_pktmbuf_pool_private), > rte_pktmbuf_pool_init, NULL, > rte_pktmbuf_init, NULL, > rte_socket_id(), 0); > > ret = rte_eth_rx_queue_setup(portid, rxlcore_id, 128, > rte_eth_dev_socket_id(portid), &rx_conf, > pktmbuf_pool); > > > > >> > >> 2) Since the NIC is reassembling payloads (of one flow) into a single > >> packet, what does the Ethernet controller do with the tcp checksum > >> field in the TCP header? I am observing that each LRO packet has > >> checksum value as zero? Is that normal? I could not find any relevant > documentation on the Web. > > That's expected. > > You can search 82599 datasheet. I think that's what you're looking for. > > Thanks! > > > Regards, > --Asim > > > > >> > >> Thanks in advance, > >> --Asim
