=== LACP retransmit cause investigation (sender) === Host: pfv-tsys7 Role: sender Date: 2026-07-27T13:57:55Z 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=tg3 speed=1000 current RX ring=2047 nic2 driver=tg3 speed=1000 current RX ring=2047 --- iperf3 summary --- [SUM] 0.00-12.00 sec 2.37 GBytes 1.69 Gbits/sec 69187 sender [SUM] 0.00-12.00 sec 2.36 GBytes 1.69 Gbits/sec receiver --- TCP SNMP deltas (/proc/net/snmp) --- ActiveOpens 80334 -> 80371 delta=37 EstabResets 14 -> 21 delta=7 InSegs 3887134 -> 4130320 delta=243186 OutSegs 10112473 -> 12172271 delta=2059798 RetransSegs 259532 -> 340946 delta=81414 --- softnet_stat deltas (look for non-zero dropped_delta/squeezed_delta) --- --- NIC counter deltas (only non-zero) --- [nic1] sysfs multicast 16340 -> 16342 delta=2 [nic2] sysfs multicast 38862 -> 38872 delta=10 --- raw iperf3 tail (last 12 lines) --- [ 13] 0.00-12.00 sec 87.9 MBytes 61.4 Mbits/sec 7050 sender [ 13] 0.00-12.00 sec 87.2 MBytes 61.0 Mbits/sec receiver [ 15] 0.00-12.00 sec 538 MBytes 376 Mbits/sec 0 sender [ 15] 0.00-12.00 sec 538 MBytes 376 Mbits/sec receiver [ 17] 0.00-12.00 sec 378 MBytes 264 Mbits/sec 19608 sender [ 17] 0.00-12.00 sec 378 MBytes 264 Mbits/sec receiver [ 19] 0.00-12.00 sec 327 MBytes 229 Mbits/sec 12049 sender [ 19] 0.00-12.00 sec 327 MBytes 228 Mbits/sec receiver [SUM] 0.00-12.00 sec 2.37 GBytes 1.69 Gbits/sec 69187 sender [SUM] 0.00-12.00 sec 2.36 GBytes 1.69 Gbits/sec receiver iperf Done. =================================================================== 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. ===================================================================