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dpdk

rte_eth_tx_burst can not send packet out


A dpdk application which generate a few arp request packets and call rte_eth_tx_burst to send them out, some packets are not received by peer NIC port(this can be confirmed by using wireshark to capture the packets from the peer NIC), dpdk-proc-info shows no error count. But before call rte_eth_tx_burst let the app sleep 10s, it can send all the packets.

example codes:

main(){
  port_init();
  sleep(10);
  gen_pkt(mbuf);
  rte_eth_tx_burst(mbuf);
}

System setup: Ubuntu 20.04.2 LTS, dpdk-stable-20.11.3, I350 Gigabit Network Connection 1521, igb_uio driver

root@k8s-node:/home/dpdk-stable-20.11.3/build/app# ./dpdk-proc-info -- --xstats
EAL: No legacy callbacks, legacy socket not created
###### NIC extended statistics for port 0  #########
####################################################
rx_good_packets: 10
tx_good_packets: 32
rx_good_bytes: 1203
tx_good_bytes: 1920
rx_missed_errors: 0
rx_errors: 0
tx_errors: 0
rx_mbuf_allocation_errors: 0
rx_q0_packets: 0
rx_q0_bytes: 0
rx_q0_errors: 0
tx_q0_packets: 0
tx_q0_bytes: 0
rx_crc_errors: 0
rx_align_errors: 0
rx_symbol_errors: 0
rx_missed_packets: 0
tx_single_collision_packets: 0
tx_multiple_collision_packets: 0
tx_excessive_collision_packets: 0
tx_late_collisions: 0
tx_total_collisions: 0
tx_deferred_packets: 0
tx_no_carrier_sense_packets: 0
rx_carrier_ext_errors: 0
rx_length_errors: 0
rx_xon_packets: 0
tx_xon_packets: 0
rx_xoff_packets: 0
tx_xoff_packets: 0
rx_flow_control_unsupported_packets: 0
rx_size_64_packets: 4
rx_size_65_to_127_packets: 3
rx_size_128_to_255_packets: 3
rx_size_256_to_511_packets: 0
rx_size_512_to_1023_packets: 0
rx_size_1024_to_max_packets: 0
rx_broadcast_packets: 0
rx_multicast_packets: 10
rx_undersize_errors: 0
rx_fragment_errors: 0
rx_oversize_errors: 0
rx_jabber_errors: 0
rx_management_packets: 0
rx_management_dropped: 0
tx_management_packets: 0
rx_total_packets: 10
tx_total_packets: 32
rx_total_bytes: 1203
tx_total_bytes: 1920
tx_size_64_packets: 32
tx_size_65_to_127_packets: 0
tx_size_128_to_255_packets: 0
tx_size_256_to_511_packets: 0
tx_size_512_to_1023_packets: 0
tx_size_1023_to_max_packets: 0
tx_multicast_packets: 0
tx_broadcast_packets: 32
tx_tso_packets: 0
tx_tso_errors: 0
rx_sent_to_host_packets: 0
tx_sent_by_host_packets: 0
rx_code_violation_packets: 0
interrupt_assert_count: 0
####################################################

root@k8s-node:/home/dpdk-stable-20.11.3/build/app# ./dpdk-proc-info -- --stats
EAL: No legacy callbacks, legacy socket not created

  ######################## NIC statistics for port 0  ########################
  RX-packets: 5           RX-errors:  0           RX-bytes:  785       
  RX-nombuf:  0         
  TX-packets: 32          TX-errors:  0           TX-bytes:  1920      

  Stats reg  0 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  1 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  2 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  3 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  4 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  5 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  6 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  7 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  8 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg  9 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg 10 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg 11 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg 12 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg 13 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg 14 RX-packets: 0           RX-errors: 0           RX-bytes: 0         
  Stats reg 15 RX-packets: 0           RX-errors: 0           RX-bytes: 0         

  Stats reg  0 TX-packets: 0           TX-bytes: 0         
  Stats reg  1 TX-packets: 0           TX-bytes: 0         
  Stats reg  2 TX-packets: 0           TX-bytes: 0         
  Stats reg  3 TX-packets: 0           TX-bytes: 0         
  Stats reg  4 TX-packets: 0           TX-bytes: 0         
  Stats reg  5 TX-packets: 0           TX-bytes: 0         
  Stats reg  6 TX-packets: 0           TX-bytes: 0         
  Stats reg  7 TX-packets: 0           TX-bytes: 0         
  Stats reg  8 TX-packets: 0           TX-bytes: 0         
  Stats reg  9 TX-packets: 0           TX-bytes: 0         
  Stats reg 10 TX-packets: 0           TX-bytes: 0         
  Stats reg 11 TX-packets: 0           TX-bytes: 0         
  Stats reg 12 TX-packets: 0           TX-bytes: 0         
  Stats reg 13 TX-packets: 0           TX-bytes: 0         
  Stats reg 14 TX-packets: 0           TX-bytes: 0         
  Stats reg 15 TX-packets: 0           TX-bytes: 0         
  ############################################################################

update:
Thanks for your response, I modified the codes:

main(){
  uint32_t port_mask = 0x1;
  port_init();
  check_all_ports_link_status(port_mask);
  gen_pkt(mbuf);
  rte_eth_tx_burst(mbuf);
}

got the print logs:

Checking link status...............................
done
Port0 Link Up. Speed 1000 Mbps - full-duplex

I think the NIC should have initallized completely, but the peer NIC port still missed a lot of packets.


Solution

  • In most working cases the Physical NIC is enumerated for Duplex (full/half), speed (1, 10, 25, 40, 50, 100, 200) and negotiated for (auto/disable) within 1 second. Anything exceeding 2 or 3 seconds is the sign of connected machine or switch not able to negotiated with Duplex, speed or auto-negotiation. Hence the recommendation is

    1. update the driver, firmware on both sides if the interfaces are NIC
    2. Test out the different connection cable as link-sense might not be reaching properly
    3. in case of hub or switch try fixing speed and auto-negotiation.
    4. I do not recommend changing from FULL duplex to Half duplex (as it could be cable or SFI issue).

    As temporary work around for the time being you can use rte_eth_link_get which also states it might need It might need to wait up to 9 seconds.

    Note: easy way to test if it is cable issue is running DPDK on both ends to check time required for link to be up.

    Modified Code Snippet:

    main(){
      port_init();
      
      RTE_ETH_FOREACH_DEV(portid) {
       struct rte_eth_link link;
       memset(&link, 0, sizeof(link));
    
       do {
            retval = rte_eth_link_get_nowait(port, &link);
            if (retval < 0) {
                printf("Failed link get (port %u): %s\n",
                    port, rte_strerror(-retval));
                return retval;
            } else if (link.link_status)
                break;
            printf("Waiting for Link up on port %"PRIu16"\n", port);
            sleep(1);
        } while (!link.link_status);
      }
    
      gen_pkt(mbuf);
      rte_eth_tx_burst(mbuf);
    }
    

    or

    main(){
      port_init();
      
      RTE_ETH_FOREACH_DEV(portid) {
       struct rte_eth_link link;
       memset(&link, 0, sizeof(link));
       ret = rte_eth_link_get(portid, &link);
       if (ret < 0) {
                printf("Port %u link get failed: err=%d\n", portid, ret);
                continue;
        }
    
      gen_pkt(mbuf);
      rte_eth_tx_burst(mbuf);
    }