Interface errors, missed packets and rec overruns

GeorgePatches · Jul 22, 2024, 6:30 PM

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

GeorgePatches · Jul 22, 2024, 7:05 PM

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)

stephenw10 · Jul 29, 2024, 2:53 PM

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

GeorgePatches · Jul 29, 2024, 4:19 PM

@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?

stephenw10 · Jul 29, 2024, 6:03 PM

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.

GeorgePatches · Jul 29, 2024, 8:05 PM

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.

GeorgePatches · Jul 29, 2024, 8:39 PM

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.

stephenw10 · Jul 29, 2024, 9:55 PM

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

GeorgePatches · Jul 30, 2024, 12:40 PM

@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.

GeorgePatches · Jul 30, 2024, 12:51 PM

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.

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

stephenw10 · Jul 30, 2024, 1:18 PM

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.

GeorgePatches · Jul 30, 2024, 1:58 PM

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.