I'm seeing considerable packet loss running recursive DNS (BIND 9.12.2) on 11.2. This is on server grade hardware (HP DL380G8) with an Intel 10Gb NIC (ix). I spun up iperf3; the results were disappointing: $ iperf3 --get-server-output -c r5 -u -b 1g -R Connecting to host r5, port 5201 Reverse mode, remote host r5 is sending [ 5] local xxx.xxx.242.11 port 56921 connected to xxx.xxx.235.238 port 5201 [ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams [ 5] 0.00-1.00 sec 77.0 MBytes 645 Mbits/sec 0.003 ms 32835/88105 (37%) [ 5] 1.00-2.00 sec 72.2 MBytes 605 Mbits/sec 0.002 ms 33813/85638 (39%) [ 5] 2.00-3.00 sec 71.3 MBytes 599 Mbits/sec 0.003 ms 34291/85534 (40%) [ 5] 3.00-4.00 sec 70.0 MBytes 587 Mbits/sec 0.012 ms 35459/85757 (41%) [ 5] 4.00-5.00 sec 71.9 MBytes 603 Mbits/sec 0.002 ms 34053/85688 (40%) [ 5] 5.00-6.00 sec 72.7 MBytes 609 Mbits/sec 0.004 ms 33354/85555 (39%) [ 5] 6.00-7.00 sec 71.7 MBytes 602 Mbits/sec 0.002 ms 33984/85472 (40%) [ 5] 7.00-8.00 sec 71.0 MBytes 596 Mbits/sec 0.002 ms 34618/85623 (40%) [ 5] 8.00-9.00 sec 70.8 MBytes 594 Mbits/sec 0.002 ms 34773/85630 (41%) [ 5] 9.00-10.00 sec 71.3 MBytes 598 Mbits/sec 0.002 ms 34593/85784 (40%) - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Jitter Lost/Total Datagrams [ 5] 0.00-10.00 sec 1.17 GBytes 1.00 Gbits/sec 0.000 ms 0/858786 (0%) sender [ 5] 0.00-10.00 sec 720 MBytes 604 Mbits/sec 0.002 ms 341773/858786 (40%) receiver Server output: ----------------------------------------------------------- Accepted connection from xxx.xxx.242.11, port 54163 [ 5] local xxx.xxx.235.238 port 5201 connected to xxx.xxx.242.11 port 56921 [ ID] Interval Transfer Bandwidth Total Datagrams [ 5] 0.00-1.00 sec 111 MBytes 930 Mbits/sec 79657 [ 5] 1.00-2.00 sec 119 MBytes 999 Mbits/sec 85536 [ 5] 2.00-3.00 sec 119 MBytes 1.00 Gbits/sec 85625 [ 5] 3.00-4.00 sec 119 MBytes 999 Mbits/sec 85541 [ 5] 4.00-5.00 sec 119 MBytes 1.00 Gbits/sec 85667 [ 5] 5.00-6.00 sec 119 MBytes 1000 Mbits/sec 85592 [ 5] 6.00-7.00 sec 119 MBytes 1.00 Gbits/sec 85720 [ 5] 7.00-8.00 sec 119 MBytes 998 Mbits/sec 85457 [ 5] 8.00-9.00 sec 119 MBytes 1.00 Gbits/sec 85622 [ 5] 9.00-10.00 sec 119 MBytes 1000 Mbits/sec 85603 [ 5] 10.00-10.10 sec 12.2 MBytes 1.02 Gbits/sec 8767 - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 5] 0.00-10.10 sec 1.17 GBytes 993 Mbits/sec 0.000 ms 0/858787 (0%) 40% loss at 1Gb. I'm running with the following tunes, which did improve DNS service when I applied them: dev.ix.0.tx_processing_limit: -1 hw.ix.flow_control: 0 hw.ix.num_queues: 8 hw.ix.rx_process_limit: -1 hw.ix.rxd: 2048 hw.ix.tx_process_limit: -1 hw.ix.txd: 2048 kern.ipc.maxsockbuf: 16777216 kern.random.harvest.mask: 351 machdep.hyperthreading_allowed: 0 net.inet.ip.intr_queue_maxlen: 2048 net.inet.raw.maxdgram: 16384 net.inet.raw.recvspace: 16384 net.isr.bindthreads: 1 net.isr.defaultqlimit: 2048 net.isr.maxthreads: 16 net.link.ifqmaxlen: 4096 net.local.stream.recvspace: 16384 net.local.stream.sendspace: 16384 net.route.netisr_maxqlen: 2048 Are there any known problems with 11.2 and UDP? Can anyone else reproduce this? Any insight or suggestions? -- Greg