IPv6 Flow offload broken?

Installing and Using OpenWrt
1

Hello,

I have upgraded from custom image (built with 18.06 branch but with 4.14 kernel on 29 Jun 2019) to 19.07.3 and the IPv6 forwrding passthrouth go from 400 Mbit/s to 147 Mbit/s
I have software flow offloading activated on my gateway

With 18.06 (custom 4.14 kernel)

[ ID] Interval           Transfer     Bitrate
[  6]   0.00-1.00   sec  11.7 MBytes  97.7 Mbits/sec                  
[  6]   1.00-2.00   sec  19.5 MBytes   164 Mbits/sec                  
[  6]   2.00-3.00   sec  47.0 MBytes   394 Mbits/sec                  
[  6]   3.00-4.00   sec  47.0 MBytes   394 Mbits/sec                  
[  6]   4.00-5.00   sec  47.0 MBytes   394 Mbits/sec                  
[  6]   5.00-6.00   sec  47.0 MBytes   394 Mbits/sec                  
[  6]   6.00-7.00   sec  47.3 MBytes   397 Mbits/sec                  
[  6]   7.00-8.00   sec  47.0 MBytes   395 Mbits/sec                  
[  6]   8.00-9.00   sec  47.1 MBytes   395 Mbits/sec                  
[  6]   9.00-10.00  sec  47.1 MBytes   395 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  6]   0.00-10.00  sec   408 MBytes   342 Mbits/sec                  sender
[  6]   0.00-10.00  sec   407 MBytes   342 Mbits/sec                  receiver

with 19.07.3

[ ID] Interval           Transfer     Bitrate
[  6]   0.00-1.00   sec  12.9 MBytes   108 Mbits/sec                  
[  6]   1.00-2.00   sec  16.9 MBytes   141 Mbits/sec                  
[  6]   2.00-3.00   sec  16.3 MBytes   137 Mbits/sec                  
[  6]   3.00-4.00   sec  16.1 MBytes   135 Mbits/sec                  
[  6]   4.00-5.00   sec  14.6 MBytes   122 Mbits/sec                  
[  6]   5.00-6.00   sec  16.1 MBytes   135 Mbits/sec                  
[  6]   6.00-7.00   sec  16.9 MBytes   141 Mbits/sec                  
[  6]   7.00-8.00   sec  16.7 MBytes   140 Mbits/sec                  
[  6]   8.00-9.00   sec  17.0 MBytes   143 Mbits/sec                  
[  6]   9.00-10.00  sec  17.1 MBytes   144 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  6]   0.00-10.00  sec   161 MBytes   135 Mbits/sec                  sender
[  6]   0.00-10.00  sec   160 MBytes   134 Mbits/sec                  receiver

My device is an Archer C7 v2

Client is a i7 powered PC on Gigabit ethernet direct in front of gateway (to eliminate a switch problem)

1 Like
2
  • What is this software?
  • Where was it executed?
  • Why are unequal file sizes used?
3

The software is iperf3, it is not a file transfer but a network transfert at the max of capacity, this is not a file size but the number of bytes successfully transmitted

So in 10sec with 18.06 (with custom kernel) i can transfer 400 Mbytes in 10 second and with 19.07.3 160 MBytes with same config

This is the scheme :

My PC on LAN Network --> Archer C7 --> L3 Switch to simulate WAN Net -> PC with iperf3 server

Edit1: with top, i see a lot of ksoftirq (90% CPU) with 19.07.3