On Fri, 27 Jun 2025, Kevin Oberman wrote:
Sorry that this took so long. I finally got around to trying an iperf3 test and it looks just about the same my speedtest. I am really surprised at the upload speed. It's about what I was seeing using netspeed, but that is about at my max upload of 40M. ifconfig shows media: IEEE 802.11 Wireless Ethernet VHT mode 11ac.
I assume the channel is equally vht/80 and the linuxkpi sysctl would not show anything else as before. Your Cwnd stays very low. Can you try UDP as well? A normal TX run here: [ ID] Interval Transfer Bitrate Retr Cwnd [ 5] 0.00-1.01 sec 95.8 MBytes 797 Mbits/sec 0 1.62 MBytes [ 5] 1.01-2.01 sec 99.8 MBytes 836 Mbits/sec 0 1.62 MBytes [ 5] 2.01-3.01 sec 99.6 MBytes 837 Mbits/sec 0 1.62 MBytes [ 5] 3.01-4.01 sec 101 MBytes 842 Mbits/sec 0 1.62 MBytes [ 5] 4.01-5.00 sec 98.6 MBytes 835 Mbits/sec 0 1.62 MBytes [ 5] 5.00-6.00 sec 100 MBytes 839 Mbits/sec 0 1.62 MBytes [ 5] 6.00-7.00 sec 100 MBytes 839 Mbits/sec 0 1.62 MBytes [ 5] 7.00-8.01 sec 94.5 MBytes 790 Mbits/sec 0 1.62 MBytes [ 5] 8.01-9.01 sec 101 MBytes 847 Mbits/sec 0 1.62 MBytes [ 5] 9.01-10.01 sec 100 MBytes 840 Mbits/sec 0 1.62 MBytes - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.01 sec 991 MBytes 831 Mbits/sec 0 sender [ 5] 0.00-10.02 sec 991 MBytes 830 Mbits/sec receiver And a TX run with retransmit (you can see the recovery): [ ID] Interval Transfer Bitrate Retr Cwnd [ 5] 0.00-1.00 sec 90.2 MBytes 753 Mbits/sec 0 1.62 MBytes [ 5] 1.00-2.03 sec 73.0 MBytes 600 Mbits/sec 0 1.62 MBytes [ 5] 2.03-3.01 sec 49.0 MBytes 417 Mbits/sec 271 313 KBytes [ 5] 3.01-4.00 sec 43.0 MBytes 364 Mbits/sec 0 483 KBytes [ 5] 4.00-5.00 sec 47.0 MBytes 394 Mbits/sec 0 615 KBytes [ 5] 5.00-6.06 sec 58.9 MBytes 466 Mbits/sec 0 729 KBytes [ 5] 6.06-7.01 sec 54.1 MBytes 480 Mbits/sec 0 811 KBytes [ 5] 7.01-8.00 sec 89.4 MBytes 752 Mbits/sec 0 871 KBytes [ 5] 8.00-9.00 sec 98.8 MBytes 829 Mbits/sec 0 914 KBytes [ 5] 9.00-10.01 sec 98.0 MBytes 817 Mbits/sec 0 943 KBytes - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.01 sec 702 MBytes 588 Mbits/sec 271 sender [ 5] 0.00-10.02 sec 702 MBytes 587 Mbits/sec receiver Here's the server side for a -R run (RX as seen from client side): [ ID] Interval Transfer Bitrate Retr Cwnd [ 5] 0.00-1.01 sec 25.4 MBytes 212 Mbits/sec 0 752 KBytes [ 5] 1.01-2.00 sec 23.5 MBytes 198 Mbits/sec 0 795 KBytes [ 5] 2.00-3.00 sec 23.5 MBytes 197 Mbits/sec 0 835 KBytes [ 5] 3.00-4.01 sec 21.9 MBytes 183 Mbits/sec 0 873 KBytes [ 5] 4.01-5.01 sec 22.2 MBytes 187 Mbits/sec 0 908 KBytes [ 5] 5.01-6.00 sec 23.1 MBytes 195 Mbits/sec 0 944 KBytes [ 5] 6.00-7.01 sec 27.0 MBytes 225 Mbits/sec 0 983 KBytes [ 5] 7.01-8.01 sec 23.4 MBytes 196 Mbits/sec 0 1017 KBytes [ 5] 8.01-9.01 sec 23.2 MBytes 195 Mbits/sec 0 1.02 MBytes [ 5] 9.01-10.01 sec 26.4 MBytes 221 Mbits/sec 0 1.13 MBytes [ 5] 10.01-10.01 sec 128 KBytes 606 Mbits/sec 0 1.13 MBytes -- Bjoern A. Zeeb r15:7
