[Banana BPI-R4] Retransmissions on SFP+ 10GB (PPPoE)

For Developers
1

Hi, i have switch to a provider that uses PPPoE over a VLAN (XGS-PON)

I am seeing retransmissions and am unable to remove them.

[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   246 MBytes  2.06 Gbits/sec   68   2.02 MBytes       
[  5]   1.00-2.00   sec   273 MBytes  2.29 Gbits/sec    6   2.16 MBytes       
[  5]   2.00-3.00   sec   273 MBytes  2.29 Gbits/sec    0   2.25 MBytes       
[  5]   3.00-4.00   sec   244 MBytes  2.04 Gbits/sec    1   1.70 MBytes       
[  5]   4.00-5.00   sec   239 MBytes  2.00 Gbits/sec    0   1.86 MBytes       
[  5]   5.00-6.00   sec   254 MBytes  2.13 Gbits/sec    0   1.98 MBytes       
[  5]   6.00-7.00   sec   269 MBytes  2.26 Gbits/sec    0   2.08 MBytes       
[  5]   7.00-8.00   sec   275 MBytes  2.31 Gbits/sec    0   2.15 MBytes       
[  5]   8.00-9.00   sec   276 MBytes  2.31 Gbits/sec    0   2.21 MBytes       
[  5]   9.00-10.00  sec   274 MBytes  2.30 Gbits/sec    0   2.25 MBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  2.56 GBytes  2.20 Gbits/sec   75             sender
[  5]   0.00-10.05  sec  2.56 GBytes  2.19 Gbits/sec                  receiver

[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   237 MBytes  1.99 Gbits/sec   96   1.92 MBytes       
[  5]   1.00-2.00   sec   261 MBytes  2.19 Gbits/sec    0   2.02 MBytes       
[  5]   2.00-3.00   sec   269 MBytes  2.26 Gbits/sec    0   2.11 MBytes       
[  5]   3.00-4.00   sec   274 MBytes  2.30 Gbits/sec    0   2.20 MBytes       
[  5]   4.00-5.00   sec   274 MBytes  2.30 Gbits/sec    0   2.29 MBytes       
[  5]   5.00-6.00   sec   275 MBytes  2.30 Gbits/sec    0   2.38 MBytes       
[  5]   6.00-7.00   sec   259 MBytes  2.17 Gbits/sec   28   1.78 MBytes       
[  5]   7.00-8.00   sec   246 MBytes  2.06 Gbits/sec    0   1.94 MBytes       
[  5]   8.00-9.00   sec   265 MBytes  2.22 Gbits/sec    0   2.08 MBytes       
[  5]   9.00-10.00  sec   274 MBytes  2.30 Gbits/sec    0   2.18 MBytes

I have tried changing MTU settings as below :

TEST1
eth2 (SFP+ wan) : 1508
eth2.[vlan] - SFP+ wan : default
wan-pppoe - SFP+ wan : 1500

TEST2
eth2 (SFP+ wan) : 1512
eth2.[vlan] - SFP+ wan : 1508
wan-pppoe - SFP+ wan : 1500

TEST3
eth2 (SFP+ wan) : 1504
eth2.[vlan] : 1500
wan-pppoe - SFP+ wan : 1492

Looking for advise on other things to try to remove these retransmissions as much as possible.

Any advise would be amazing.

Also of note is that TEST1 and TEST2 seems to break the hardware offloading and I see high (78-80% CPU usage across 2 cores when running a speed test from lan -> wan)

2

Use this guide as reference / checklist:

Red Hat 9 net tuning guide

Any scheduled task every 5 minutes? Offloads?

Please connect to your OpenWrt device using ssh and copy the output of the following commands and post it here using the "Preformatted text </> " button:
grafik
Remember to redact passwords, MAC addresses and any public IP addresses you may have:

ubus call system board
cat /etc/config/network
: cat /etc/config/wireless
cat /etc/config/dhcp
cat /etc/config/firewall