=== LACP retransmit cause investigation (receiver) === Host: pfv-tsys6 Role: receiver Date: 2026-07-27T13:57:50Z Bond: bond0 --- bond0 hash + driver --- Bonding Mode: IEEE 802.3ad Dynamic link aggregation Transmit Hash Policy: layer3+4 (1) Number of ports: 2 Partner Mac Address: 00:13:72:46:95:e4 nic1 driver=bnx2 speed=1000 current RX ring=2040 nic2 driver=bnx2 speed=1000 current RX ring=2040 --- iperf3 summary --- [SUM] 0.00-12.00 sec 2.36 GBytes 1.69 Gbits/sec receiver --- TCP SNMP deltas (/proc/net/snmp) --- ActiveOpens 82825 -> 82853 delta=28 PassiveOpens 12139 -> 12148 delta=9 EstabResets 3 -> 4 delta=1 InSegs 4295069 -> 4586141 delta=291072 OutSegs 9518841 -> 9761558 delta=242717 RetransSegs 68841 -> 68886 delta=45 OutRsts 1605 -> 1661 delta=56 --- softnet_stat deltas (look for non-zero dropped_delta/squeezed_delta) --- --- NIC counter deltas (only non-zero) --- [nic1] sysfs multicast 38589 -> 38603 delta=14 [nic2] sysfs multicast 16188 -> 16194 delta=6 --- raw iperf3 tail (last 12 lines) --- [SUM] 12.00-12.00 sec 640 KBytes 1.69 Gbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate [ 5] 0.00-12.00 sec 538 MBytes 376 Mbits/sec receiver [ 8] 0.00-12.00 sec 81.5 MBytes 57.0 Mbits/sec receiver [ 10] 0.00-12.00 sec 69.4 MBytes 48.5 Mbits/sec receiver [ 12] 0.00-12.00 sec 402 MBytes 281 Mbits/sec receiver [ 14] 0.00-12.00 sec 87.2 MBytes 61.0 Mbits/sec receiver [ 16] 0.00-12.00 sec 538 MBytes 376 Mbits/sec receiver [ 18] 0.00-12.00 sec 378 MBytes 264 Mbits/sec receiver [ 20] 0.00-12.00 sec 327 MBytes 228 Mbits/sec receiver [SUM] 0.00-12.00 sec 2.36 GBytes 1.69 Gbits/sec receiver =================================================================== HOW TO READ THIS =================================================================== - If NIC rx_dropped / rx_missed_errors / rx_fifo_errors climbed: -> ring buffers too small. Fix: ethtool -G $IF rx 4096 (or max). - If softnet_stat 'dropped' or 'squeezed' climbed on any CPU: -> softirq starvation. Fix: increase net.core.netdev_budget, check IRQ affinity, consider RPS. - If NEITHER of the above climbed but TCP RetransSegs did: -> the retransmits are LACP reordering (out-of-order segments triggering fast retransmit), NOT packet loss. NOT fixable. ===================================================================