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    Interface errors, missed packets and rec overruns

    Scheduled Pinned Locked Moved Hardware
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    • G
      GeorgePatches
      last edited by

      I'm slowly racking up interfaced errors on my CE 2.7.2 home box and I'm not sure why. It's an old firewall appliance box, a Lanner FW-7541C. It has an Intel D525 CPU, 1 Intel 82574L and 5 Intel 82583V interfaces, a SanDisk SSD storage device and 4GB of RAM. I keep missing a small number of packets. Like the majority are getting through fine and I'm not seeing any trouble, but the errors keep slowly ticking up. I have hardware offload enabled, with large send/recv disabled per the documentation recommendations. I know the D525 has all the processing power of a wet noodle, but I'm not trying to do anything processor intensive. Basically just basic firewall duty and that's it. I've tried turning hyper-threading on and off. I've tried moving the WAN from a direct line to the pfsense to passing through a switch. I've tried the 82583V's instead of the 84574L. I just don't get it, my internet is only like 300-350Mbit, I think it should be able to keep up with that, right? Is there any tweak I should try?

      sysctl dev.em.0 output

      dev.em.0.interrupts.rx_overrun: 3
      dev.em.0.interrupts.rx_desc_min_thresh: 0
      dev.em.0.interrupts.tx_queue_min_thresh: 1
      dev.em.0.interrupts.tx_queue_empty: 0
      dev.em.0.interrupts.tx_abs_timer: 2
      dev.em.0.interrupts.tx_pkt_timer: 1
      dev.em.0.interrupts.rx_abs_timer: 0
      dev.em.0.interrupts.rx_pkt_timer: 32
      dev.em.0.interrupts.asserts: 118670
      dev.em.0.mac_stats.tso_ctx_fail: 0
      dev.em.0.mac_stats.tso_txd: 0
      dev.em.0.mac_stats.tx_frames_1024_1522: 181167932
      dev.em.0.mac_stats.tx_frames_512_1023: 7667118
      dev.em.0.mac_stats.tx_frames_256_511: 7806568
      dev.em.0.mac_stats.tx_frames_128_255: 14078839
      dev.em.0.mac_stats.tx_frames_65_127: 54260108
      dev.em.0.mac_stats.tx_frames_64: 48427909
      dev.em.0.mac_stats.mcast_pkts_txd: 1884495
      dev.em.0.mac_stats.bcast_pkts_txd: 45661
      dev.em.0.mac_stats.good_pkts_txd: 313408474
      dev.em.0.mac_stats.total_pkts_txd: 313436934
      dev.em.0.mac_stats.good_octets_txd: 285602451945
      dev.em.0.mac_stats.good_octets_recvd: 287772957030
      dev.em.0.mac_stats.rx_frames_1024_1522: 182980173
      dev.em.0.mac_stats.rx_frames_512_1023: 7219728
      dev.em.0.mac_stats.rx_frames_256_511: 7331488
      dev.em.0.mac_stats.rx_frames_128_255: 12598599
      dev.em.0.mac_stats.rx_frames_65_127: 98395148
      dev.em.0.mac_stats.rx_frames_64: 4681295
      dev.em.0.mac_stats.mcast_pkts_recvd: 286677
      dev.em.0.mac_stats.bcast_pkts_recvd: 2006878
      dev.em.0.mac_stats.good_pkts_recvd: 313206431
      dev.em.0.mac_stats.total_pkts_recvd: 313284437
      dev.em.0.mac_stats.xoff_txd: 25803
      dev.em.0.mac_stats.xoff_recvd: 22665
      dev.em.0.mac_stats.xon_txd: 2657
      dev.em.0.mac_stats.xon_recvd: 22305
      dev.em.0.mac_stats.coll_ext_errs: 0
      dev.em.0.mac_stats.alignment_errs: 0
      dev.em.0.mac_stats.crc_errs: 0
      dev.em.0.mac_stats.recv_errs: 0
      dev.em.0.mac_stats.recv_jabber: 0
      dev.em.0.mac_stats.recv_oversize: 0
      dev.em.0.mac_stats.recv_fragmented: 0
      dev.em.0.mac_stats.recv_undersize: 0
      dev.em.0.mac_stats.recv_no_buff: 20674810
      dev.em.0.mac_stats.missed_packets: 23148
      dev.em.0.mac_stats.defer_count: 0
      dev.em.0.mac_stats.sequence_errors: 0
      dev.em.0.mac_stats.symbol_errors: 0
      dev.em.0.mac_stats.collision_count: 0
      dev.em.0.mac_stats.late_coll: 0
      dev.em.0.mac_stats.multiple_coll: 0
      dev.em.0.mac_stats.single_coll: 0
      dev.em.0.mac_stats.excess_coll: 0
      dev.em.0.queue_rx_1.rx_irq: 0
      dev.em.0.queue_rx_1.rxd_tail: 802
      dev.em.0.queue_rx_1.rxd_head: 803
      dev.em.0.queue_rx_0.rx_irq: 0
      dev.em.0.queue_rx_0.rxd_tail: 616
      dev.em.0.queue_rx_0.rxd_head: 617
      dev.em.0.queue_tx_1.tx_irq: 0
      dev.em.0.queue_tx_1.txd_tail: 507
      dev.em.0.queue_tx_1.txd_head: 510
      dev.em.0.queue_tx_0.tx_irq: 0
      dev.em.0.queue_tx_0.txd_tail: 543
      dev.em.0.queue_tx_0.txd_head: 543
      dev.em.0.fc_low_water: 16932
      dev.em.0.fc_high_water: 18432
      dev.em.0.rx_control: 67403778
      dev.em.0.device_control: 1477444168
      dev.em.0.watchdog_timeouts: 0
      dev.em.0.rx_overruns: 81652
      dev.em.0.link_irq: 123229
      dev.em.0.dropped: 0
      dev.em.0.eee_control: 1
      dev.em.0.itr: 488
      dev.em.0.tx_abs_int_delay: 66
      dev.em.0.rx_abs_int_delay: 66
      dev.em.0.tx_int_delay: 66
      dev.em.0.rx_int_delay: 0
      dev.em.0.rs_dump: 0
      dev.em.0.reg_dump: General Registers
      	CTRL	 58100248
      	STATUS	 00080783
      	CTRL_EXT	 80580000
      
      Interrupt Registers
      	ICR	 80000001
      
      RX Registers
      	RCTL	 04048002
      	RDLEN	 00004000
      	RDH	 00000269
      	RDT	 00000268
      	RXDCTL	 01050420
      	RDBAL	 0461a000
      	RDBAH	 00000000
      
      TX Registers
      	TCTL	 3103f0fa
      	TDBAL	 04600000
      	TDBAH	 00000000
      	TDLEN	 00004000
      	TDH	 0000021f
      	TDT	 0000021f
      	TXDCTL	 0341011f
      	TDFH	 00000b28
      	TDFT	 00000b28
      	TDFHS	 00000b28
      	TDFPC	 00000000
      
      
      dev.em.0.fc: 3
      dev.em.0.debug: -1
      dev.em.0.fw_version: EEPROM V1.9-0
      dev.em.0.nvm: -1
      dev.em.0.iflib.rxq1.rxq_fl0.buf_size: 2048
      dev.em.0.iflib.rxq1.rxq_fl0.credits: 1023
      dev.em.0.iflib.rxq1.rxq_fl0.cidx: 818
      dev.em.0.iflib.rxq1.rxq_fl0.pidx: 817
      dev.em.0.iflib.rxq1.cpu: 2
      dev.em.0.iflib.rxq0.rxq_fl0.buf_size: 2048
      dev.em.0.iflib.rxq0.rxq_fl0.credits: 1023
      dev.em.0.iflib.rxq0.rxq_fl0.cidx: 617
      dev.em.0.iflib.rxq0.rxq_fl0.pidx: 616
      dev.em.0.iflib.rxq0.cpu: 0
      dev.em.0.iflib.txq1.r_abdications: 0
      dev.em.0.iflib.txq1.r_restarts: 0
      dev.em.0.iflib.txq1.r_stalls: 0
      dev.em.0.iflib.txq1.r_starts: 148037804
      dev.em.0.iflib.txq1.r_drops: 0
      dev.em.0.iflib.txq1.r_enqueues: 152658558
      dev.em.0.iflib.txq1.ring_state: pidx_head: 0640 pidx_tail: 0640 cidx: 0640 state: IDLE
      dev.em.0.iflib.txq1.txq_cleaned: 171150878
      dev.em.0.iflib.txq1.txq_processed: 171150918
      dev.em.0.iflib.txq1.txq_in_use: 45
      dev.em.0.iflib.txq1.txq_cidx_processed: 587
      dev.em.0.iflib.txq1.txq_cidx: 550
      dev.em.0.iflib.txq1.txq_pidx: 592
      dev.em.0.iflib.txq1.no_tx_dma_setup: 0
      dev.em.0.iflib.txq1.txd_encap_efbig: 0
      dev.em.0.iflib.txq1.tx_map_failed: 0
      dev.em.0.iflib.txq1.no_desc_avail: 0
      dev.em.0.iflib.txq1.mbuf_defrag_failed: 0
      dev.em.0.iflib.txq1.m_pullups: 12029099
      dev.em.0.iflib.txq1.mbuf_defrag: 0
      dev.em.0.iflib.txq1.cpu: 2
      dev.em.0.iflib.txq0.r_abdications: 0
      dev.em.0.iflib.txq0.r_restarts: 91
      dev.em.0.iflib.txq0.r_stalls: 91
      dev.em.0.iflib.txq0.r_starts: 156570070
      dev.em.0.iflib.txq0.r_drops: 0
      dev.em.0.iflib.txq0.r_enqueues: 160858354
      dev.em.0.iflib.txq0.ring_state: pidx_head: 0242 pidx_tail: 0242 cidx: 0242 state: IDLE
      dev.em.0.iflib.txq0.txq_cleaned: 177709558
      dev.em.0.iflib.txq0.txq_processed: 177709598
      dev.em.0.iflib.txq0.txq_in_use: 41
      dev.em.0.iflib.txq0.txq_cidx_processed: 542
      dev.em.0.iflib.txq0.txq_cidx: 502
      dev.em.0.iflib.txq0.txq_pidx: 543
      dev.em.0.iflib.txq0.no_tx_dma_setup: 0
      dev.em.0.iflib.txq0.txd_encap_efbig: 0
      dev.em.0.iflib.txq0.tx_map_failed: 0
      dev.em.0.iflib.txq0.no_desc_avail: 0
      dev.em.0.iflib.txq0.mbuf_defrag_failed: 0
      dev.em.0.iflib.txq0.m_pullups: 12129578
      dev.em.0.iflib.txq0.mbuf_defrag: 0
      dev.em.0.iflib.txq0.cpu: 0
      dev.em.0.iflib.override_nrxds: 0
      dev.em.0.iflib.override_ntxds: 0
      dev.em.0.iflib.use_logical_cores: 0
      dev.em.0.iflib.separate_txrx: 0
      dev.em.0.iflib.core_offset: 0
      dev.em.0.iflib.tx_abdicate: 0
      dev.em.0.iflib.rx_budget: 0
      dev.em.0.iflib.disable_msix: 0
      dev.em.0.iflib.override_qs_enable: 0
      dev.em.0.iflib.override_nrxqs: 0
      dev.em.0.iflib.override_ntxqs: 0
      dev.em.0.iflib.driver_version: 7.7.8-fbsd
      dev.em.0.%parent: pci1
      dev.em.0.%pnpinfo: vendor=0x8086 device=0x10d3 subvendor=0x8086 subdevice=0x0000 class=0x020000
      dev.em.0.%location: slot=0 function=0 dbsf=pci0:2:0:0
      dev.em.0.%driver: em
      dev.em.0.%desc: Intel(R) Gigabit CT 82574L
      
      
      1 Reply Last reply Reply Quote 0
      • G
        GeorgePatches
        last edited by GeorgePatches

        Oh, I forgot possibly the most interesting tidbit. My brother is experiencing the same behavior and his system has a Ryzen 3 2200G. CPU to spare on that machine with an old quad NIC Intel 82571. It only seems to happen on the WAN side. I had the same experience when my WAN was separate. (I currently have all my traffic VLANed into a single physical NIC).

        Brother's sysctl dev.em.0 output

        dev.em.0.interrupts.rx_overrun: 0
        dev.em.0.interrupts.rx_desc_min_thresh: 0
        dev.em.0.interrupts.tx_queue_min_thresh: 24
        dev.em.0.interrupts.tx_queue_empty: 0
        dev.em.0.interrupts.tx_abs_timer: 9824
        dev.em.0.interrupts.tx_pkt_timer: 7967
        dev.em.0.interrupts.rx_abs_timer: 0
        dev.em.0.interrupts.rx_pkt_timer: 80527
        dev.em.0.interrupts.asserts: 484449432
        dev.em.0.mac_stats.tso_ctx_fail: 0
        dev.em.0.mac_stats.tso_txd: 0
        dev.em.0.mac_stats.tx_frames_1024_1522: 83478008
        dev.em.0.mac_stats.tx_frames_512_1023: 619494980
        dev.em.0.mac_stats.tx_frames_256_511: 4447683
        dev.em.0.mac_stats.tx_frames_128_255: 26350772
        dev.em.0.mac_stats.tx_frames_65_127: 90891554
        dev.em.0.mac_stats.tx_frames_64: 42590904
        dev.em.0.mac_stats.mcast_pkts_txd: 1192
        dev.em.0.mac_stats.bcast_pkts_txd: 3346
        dev.em.0.mac_stats.good_pkts_txd: 867253901
        dev.em.0.mac_stats.total_pkts_txd: 867253901
        dev.em.0.mac_stats.good_octets_txd: 564113139828
        dev.em.0.mac_stats.good_octets_recvd: 600386896379
        dev.em.0.mac_stats.rx_frames_1024_1522: 395679755
        dev.em.0.mac_stats.rx_frames_512_1023: 17668892
        dev.em.0.mac_stats.rx_frames_256_511: 7229265
        dev.em.0.mac_stats.rx_frames_128_255: 158134130
        dev.em.0.mac_stats.rx_frames_65_127: 48923871
        dev.em.0.mac_stats.rx_frames_64: 0
        dev.em.0.mac_stats.mcast_pkts_recvd: 6626
        dev.em.0.mac_stats.bcast_pkts_recvd: 0
        dev.em.0.mac_stats.good_pkts_recvd: 627635913
        dev.em.0.mac_stats.total_pkts_recvd: 629974672
        dev.em.0.mac_stats.xoff_txd: 0
        dev.em.0.mac_stats.xoff_recvd: 1165746
        dev.em.0.mac_stats.xon_txd: 0
        dev.em.0.mac_stats.xon_recvd: 1165746
        dev.em.0.mac_stats.coll_ext_errs: 0
        dev.em.0.mac_stats.alignment_errs: 0
        dev.em.0.mac_stats.crc_errs: 0
        dev.em.0.mac_stats.recv_errs: 0
        dev.em.0.mac_stats.recv_jabber: 0
        dev.em.0.mac_stats.recv_oversize: 0
        dev.em.0.mac_stats.recv_fragmented: 0
        dev.em.0.mac_stats.recv_undersize: 0
        dev.em.0.mac_stats.recv_no_buff: 0
        dev.em.0.mac_stats.missed_packets: 7310
        dev.em.0.mac_stats.defer_count: 1161488
        dev.em.0.mac_stats.sequence_errors: 0
        dev.em.0.mac_stats.symbol_errors: 0
        dev.em.0.mac_stats.collision_count: 0
        dev.em.0.mac_stats.late_coll: 0
        dev.em.0.mac_stats.multiple_coll: 0
        dev.em.0.mac_stats.single_coll: 0
        dev.em.0.mac_stats.excess_coll: 0
        dev.em.0.queue_rx_0.rx_irq: 0
        dev.em.0.queue_rx_0.rxd_tail: 518
        dev.em.0.queue_rx_0.rxd_head: 519
        dev.em.0.queue_tx_0.tx_irq: 0
        dev.em.0.queue_tx_0.txd_tail: 164
        dev.em.0.queue_tx_0.txd_head: 164
        dev.em.0.fc_low_water: 29220
        dev.em.0.fc_high_water: 30720
        dev.em.0.rx_control: 67403778
        dev.em.0.device_control: 1209795137
        dev.em.0.watchdog_timeouts: 0
        dev.em.0.rx_overruns: 111
        dev.em.0.link_irq: 0
        dev.em.0.dropped: 0
        dev.em.0.eee_control: 1
        dev.em.0.itr: 488
        dev.em.0.tx_abs_int_delay: 66
        dev.em.0.rx_abs_int_delay: 66
        dev.em.0.tx_int_delay: 66
        dev.em.0.rx_int_delay: 0
        dev.em.0.rs_dump: 0
        dev.em.0.reg_dump: General Registers
        	CTRL	 481c0241
        	STATUS	 00080387
        	CTRL_EXT	 101400c0
        
        Interrupt Registers
        	ICR	 00000000
        
        RX Registers
        	RCTL	 04048002
        	RDLEN	 00004000
        	RDH	 00000207
        	RDT	 00000206
        	RXDCTL	 00010000
        	RDBAL	 b0034000
        	RDBAH	 00000000
        
        TX Registers
        	TCTL	 3103f0fa
        	TDBAL	 b002c000
        	TDBAH	 00000000
        	TDLEN	 00004000
        	TDH	 000000aa
        	TDT	 000000aa
        	TXDCTL	 0341011f
        	TDFH	 00001296
        	TDFT	 00001298
        	TDFHS	 00001296
        	TDFPC	 00000000
        
        
        dev.em.0.fc: 3
        dev.em.0.debug: -1
        dev.em.0.fw_version: EEPROM V5.12-2
        dev.em.0.nvm: -1
        dev.em.0.iflib.rxq0.rxq_fl0.buf_size: 2048
        dev.em.0.iflib.rxq0.rxq_fl0.credits: 1023
        dev.em.0.iflib.rxq0.rxq_fl0.cidx: 519
        dev.em.0.iflib.rxq0.rxq_fl0.pidx: 518
        dev.em.0.iflib.rxq0.cpu: 3
        dev.em.0.iflib.txq0.r_abdications: 324
        dev.em.0.iflib.txq0.r_restarts: 56590
        dev.em.0.iflib.txq0.r_stalls: 56590
        dev.em.0.iflib.txq0.r_starts: 858032115
        dev.em.0.iflib.txq0.r_drops: 1072
        dev.em.0.iflib.txq0.r_enqueues: 868117756
        dev.em.0.iflib.txq0.ring_state: pidx_head: 1279 pidx_tail: 1279 cidx: 1279 state: IDLE
        dev.em.0.iflib.txq0.txq_cleaned: 1474843782
        dev.em.0.iflib.txq0.txq_processed: 1474843822
        dev.em.0.iflib.txq0.txq_in_use: 44
        dev.em.0.iflib.txq0.txq_cidx_processed: 174
        dev.em.0.iflib.txq0.txq_cidx: 134
        dev.em.0.iflib.txq0.txq_pidx: 178
        dev.em.0.iflib.txq0.no_tx_dma_setup: 0
        dev.em.0.iflib.txq0.txd_encap_efbig: 0
        dev.em.0.iflib.txq0.tx_map_failed: 0
        dev.em.0.iflib.txq0.no_desc_avail: 0
        dev.em.0.iflib.txq0.mbuf_defrag_failed: 0
        dev.em.0.iflib.txq0.m_pullups: 602346602
        dev.em.0.iflib.txq0.mbuf_defrag: 0
        dev.em.0.iflib.txq0.cpu: 2
        dev.em.0.iflib.override_nrxds: 0
        dev.em.0.iflib.override_ntxds: 0
        dev.em.0.iflib.use_logical_cores: 0
        dev.em.0.iflib.separate_txrx: 0
        dev.em.0.iflib.core_offset: 0
        dev.em.0.iflib.tx_abdicate: 0
        dev.em.0.iflib.rx_budget: 0
        dev.em.0.iflib.disable_msix: 1
        dev.em.0.iflib.override_qs_enable: 0
        dev.em.0.iflib.override_nrxqs: 0
        dev.em.0.iflib.override_ntxqs: 0
        dev.em.0.iflib.driver_version: 7.7.8-fbsd
        dev.em.0.%parent: pci3
        dev.em.0.%pnpinfo: vendor=0x8086 device=0x10bc subvendor=0x103c subdevice=0x704b class=0x020000
        dev.em.0.%location: slot=0 function=0 dbsf=pci0:18:0:0
        dev.em.0.%driver: em
        dev.em.0.%desc: Intel(R) PRO/1000 PT 82571EB/82571GB (Quad Copper)
        
        
        1 Reply Last reply Reply Quote 0
        • stephenw10S
          stephenw10 Netgate Administrator
          last edited by

          Looks like slightly different cause though. recv_no_buff vs defer_count

          The first thing I'd try is reassigning the NICs to use a different one as WAN and see if the issue follows it.

          Next I'd try a different flow-control setting and check the current negotiated value. That should prevent the other side overloading the receive buffers if both ends support it.

          Steve

          G 1 Reply Last reply Reply Quote 0
          • G
            GeorgePatches @stephenw10
            last edited by

            @stephenw10 said in Interface errors, missed packets and rec overruns:

            Looks like slightly different cause though. recv_no_buff vs defer_count

            I noticed that too, but I'm not sure what "defer" means here. I mean I'm also not sure what "recv_no_buff" means, but my educated guess is it received a packet but had no buffer space available to place it in.

            @stephenw10 said in Interface errors, missed packets and rec overruns:

            The first thing I'd try is reassigning the NICs to use a different one as WAN and see if the issue follows it.

            I tried that already, the 82583V NICs all do the same thing.

            @stephenw10 said in Interface errors, missed packets and rec overruns:

            Next I'd try a different flow-control setting and check the current negotiated value.

            So it's currently set to 3 for flow control. How do I check the negotiated value?

            1 Reply Last reply Reply Quote 0
            • stephenw10S
              stephenw10 Netgate Administrator
              last edited by

              AFAIK recv_no_buff implies there are no available receive buffers. So potentially you could increase the buffers.

              I will say that I see some no_buff failures on a box here and don't see any connection issues:

              [2.7.2-RELEASE][admin@xtm5.stevew.lan]/root: sysctl dev.em.0 | grep buf
              dev.em.0.mac_stats.recv_no_buff: 36
              dev.em.0.iflib.rxq1.rxq_fl0.buf_size: 2048
              dev.em.0.iflib.rxq0.rxq_fl0.buf_size: 2048
              dev.em.0.iflib.txq1.mbuf_defrag_failed: 0
              dev.em.0.iflib.txq1.mbuf_defrag: 0
              dev.em.0.iflib.txq0.mbuf_defrag_failed: 0
              dev.em.0.iflib.txq0.mbuf_defrag: 0
              

              Good question about seeing how it's linked though! em doesn't appear to report that. I'd try setting fc to 0 and see if that changes anything.

              1 Reply Last reply Reply Quote 0
              • G
                GeorgePatches
                last edited by GeorgePatches

                OK, I found some interesting things. Turns out old Intel datasheets have really thorough descriptions of what all these counters mean. Intel 82583V datasheet

                Defer Count: This register counts defer events. A defer event occurs when the transmitter cannot immediately send a packet due to the medium being busy either because:
                • Another device is transmitting
                • The IPG timer has not expired
                • Half-duplex deferral events
                • Reception of XOFF frames
                • The link is not up
                This register only increments if transmits are enabled. The behavior of this counter is slightly different in the 82583V relative to previous devices. For the 82583V, this counter does not increment for streaming transmits that are deferred due to TX IPG.

                Receive No Buffers Count: This register counts the number of times that frames were received when there were no available buffers in host memory to store those frames (receive descriptor head and tail pointers were equal). The packet is still received if there is space in the FIFO. This register only increments if receives are enabled. This register does not increment when flow control packets are received.

                Missed Packets Count: Counts the number of missed packets. Packets are missed when the receive FIFO has insufficient space to store the incoming packet. This could be caused because of too few buffers allocated, or because there is insufficient bandwidth on the IO bus. Events setting this counter cause RXO, the receiver overrun interrupt, to be set. This register does not increment if receives are not enabled. Note that these packets are also counted in the Total Packets Received register as well as in the Total Octets Received register.

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                • G
                  GeorgePatches
                  last edited by

                  So Defers are specifically transmits and won't ever be Missed packets. And Recv_No_Buff is the NIC has a frame, but the CPU has no buffer for it. Recv_no_buff can become missed_packets if the situation persists long enough.

                  I reconfigured things. Instead of shoving everything into em.0 in a router on a stick config, I changed em.0 to be the only WAN and all the LAN VLANs on em.1. This was weird as I can literally just watch the recv_no_buff incrementing on em.0, but em.1 which is seeing the same number of packets is not having any trouble.

                  Then I reconfigured things again, this time put the WAN on em.5 and the LAN VLANs on em.4. This setup has no immediate issues, but in the past it slowly accumulates errors just the same.

                  My brother's stats confuse me. Defers seem like they should mostly not happen on a full-duplex link, but maybe this is older hardware that increments this when XOFF is received. His defers count is very similar to the XOFF received count. More confusing is that he's getting missed packets, but without recv_no_buff. That doesn't seem like it should be possible.

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                  • stephenw10S
                    stephenw10 Netgate Administrator
                    last edited by

                    Hmm, interesting. Are those all the exact same NIC chip? Different PCIe bus maybe?

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                    • G
                      GeorgePatches @stephenw10
                      last edited by

                      @stephenw10 em.0 is a 82574L, but em.1-5 are 82583V's. According to pciconf I think they all have a direct x1 lane to the CPU.

                      My brother is using an old HP 4 port nic with 82571 chips. I'm starting to think the older 82571 just doesn't have the recv_no_buff register.

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                      • G
                        GeorgePatches @GeorgePatches
                        last edited by

                        Actually I just found a bit in the 2014 errata update for the 82571EB that might explain my brother's missed packets. It might just be old crap.

                        1. Missed RX Packets

                        Problem:
                        When the device operates with multiple-requests or Large Send enabled, there could be receive packet loss. When the Tx FIFO is full, the Tx flow may block the host DMA interface of the device. When the transmission of packets is prevented for a long time, due to capture effect or very long backoff in half-duplex, the transmit FIFO is filled and the fetch of Rx descriptors is prevented also. This will prevent the release of the packets from the Rx FIFO to the host, causing the Rx buffer to overflow and the loss of incoming packets. This is a temporary state that will be released once the transmit side is be able to empty the Tx packet buffer.

                        Implication:
                        There could be some packet loss in the Rx path if the transmission of packets is prevented for a long time. Normally, if this occurs, these packets will be re-transmitted by upper-layer protocols.

                        Workaround:
                        None

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                        • stephenw10S
                          stephenw10 Netgate Administrator
                          last edited by

                          Hmm the 82574 is extremely common. I would have expected that to work more reliably if anything. But there is a difference there so whatever is causing a problem on em0 the 82583V apparently doesn't suffer from it.

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                          • G
                            GeorgePatches
                            last edited by

                            Of the 2 options I have on this box it's supposed to be the "better" one. It has MSI-X and dual tx/rx queues to the 82583V's MSI and single tx/rx queue. 🤷

                            Also, I definitely had the em.5/WAN em.4/LAN setup in the past and it would miss packets over time, but this time it's all good. 🤷

                            Only I've reconfigured this so many times and it's never worked as well as it finally is. Computers man, what the hell.

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