Some LAN<->WAN iperf3 tests, made with 2 intel gigabit computers, running last linux mint in usb pens.

Only had time to test some of the options, so in all the bellow tests, Routing/NAT Offloading options were:
Software flow offloading = ENABLE (Didn't tried Disable).
Hardware flow offloading = DISABLE (Didn't tried Enable).

I made different test with:
Packet Stearing Enable/Disable (Had to reboot after changing Enable or Disable to take effect).
Made big speed difference only when iperf3 --bidir switch was used.
Irqbalance Enable/Disable (I could not see any noticable difference with Enabled or Disabled).

Test #1:
Packet Stearing Enable; irqbalance Enable
See iperf3 --bidir option takes 100% of one core, but speed always ~930Mbits.

- - - - - - - - - - - - - - - - - - - - - - - - -
**iperf3 -c 192.168.0.110 -t 30**
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-30.00  sec  3.27 GBytes   935 Mbits/sec    0             sender
[  5]   0.00-30.00  sec  3.26 GBytes   934 Mbits/sec                  receiver
- - - - - - - - - - - - - - - - - - - - - - - - -
    0[||||||||||||||||||||||||||||||||                58.9%] Tasks: 25, 9 thr, 78 kthr; 1 running
    1[|||                                              4.9%] Load average: 0.31 0.10 0.03 
    2[|                                                0.7%] Uptime: 05:42:08
    3[||                                               1.3%]
  Mem[|||||||||||||||||||||||||||                 154M/408M]
  Swp[                                                0K/0K]

  PID USER       PRI  NI  VIRT   RES   SHR S CPU%-MEM%   TIME+  Command
11309 root        20   0  2284  2008  1112 R  1.8  0.5  0:25.16 htop
   10 root        20   0     0     0     0 S  0.9  0.0  3:53.90 ksoftirqd/0
11300 root        20   0  1064   732   660 S  0.9  0.2  0:00.75 /usr/sbin/dropbear -F -P /var/run/dropbear.1.pid -p 192.
    1 root        20   0  1664  1120   864 S  0.0  0.3  0:01.58 /sbin/procd
-----------------------------------------------------------------------------------------
- - - - - - - - - - - - - - - - - - - - - - - - -
**iperf3 -c 192.168.0.110 --bidir -t 30**
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval           Transfer     Bitrate         Retr
[  5][TX-C]   0.00-30.00  sec  3.25 GBytes   931 Mbits/sec  123             sender
[  5][TX-C]   0.00-30.00  sec  3.25 GBytes   930 Mbits/sec                  receiver
[  7][RX-C]   0.00-30.00  sec  3.25 GBytes   931 Mbits/sec  112             sender
[  7][RX-C]   0.00-30.00  sec  3.25 GBytes   930 Mbits/sec                  receiver
- - - - - - - - - - - - - - - - - - - - - - - - -
    0[||||||||||||||||||||||||||||||||||||||||||||||||99.2%] Tasks: 25, 9 thr, 78 kthr; 2 running
    1[||||||||||                                      18.5%] Load average: 0.01 0.04 0.00 
    2[                                                 0.0%] Uptime: 05:48:35
    3[|                                                1.4%]
  Mem[|||||||||||||||||||||||||||                 155M/408M]
  Swp[                                                0K/0K]

  PID USER       PRI  NI  VIRT   RES   SHR S CPU%-MEM%   TIME+  Command
   10 root        20   0     0     0     0 S 81.8  0.0  4:24.54 ksoftirqd/0
   16 root        20   0     0     0     0 S  1.8  0.0  0:01.05 ksoftirqd/1
11309 root        20   0  2284  2008  1112 R  1.8  0.5  0:30.01 htop
11300 root        20   0  1064   732   660 S  0.9  0.2  0:00.90 /usr/sbin/dropbear -F -P /var/run/dropbear.1.pid -p 192.
    1 root        20   0  1664  1120   864 S  0.0  0.3  0:01.58 /sbin/procd
-----------------------------------------------------------------------------------------
**cat /proc/interrupts**
           CPU0       CPU1       CPU2       CPU3       
 11:     390582     199648     366107     185775     GIC-0  20 Level     arch_timer
 13:          0          0          0          0     GIC-0  39 Level     arch_mem_timer
 16:          2          0          0          0     GIC-0 354 Edge      smp2p
 17:          0          0          0          0     GIC-0 216 Level     4a9000.thermal-sensor
 18:          0          0          0          0     GIC-0 239 Level     bam_dma
 21:          0          0          0          0     GIC-0 270 Level     bam_dma
 22:          6          0          0          0     GIC-0 340 Level     msm_serial0
 23:      45752          0          0          0     GIC-0 178 Level     bam_dma
 24:          0          0          0          0     GIC-0  35 Edge      wdt_bark
 25:          0          0          0          0     GIC-0 357 Edge      q6v5 wdog
 29:          5          0          0          0     GIC-0 348 Edge      ce0
 30:      65855          0          0          0     GIC-0 347 Edge      ce1
 31:      17163          0          0          0     GIC-0 346 Edge      ce2
 32:       1047          0          0          0     GIC-0 343 Edge      ce3
 34:          1          0          0          0     GIC-0 443 Edge      ce5
 36:       1204          0          0          0     GIC-0  72 Edge      ce7
 38:          0          0          0          0     GIC-0 334 Edge      ce9
 39:          1          0          0          0     GIC-0 333 Edge      ce10
 40:          0          0          0          0     GIC-0  69 Edge      ce11
 47:          0          0          0          0     GIC-0 323 Edge      reo2ost-exception
 48:        157          0          0          0     GIC-0 322 Edge      wbm2host-rx-release
 49:         28          0          0          0     GIC-0 321 Edge      reo2host-status
 50:       1717          0          0          0     GIC-0 320 Edge      reo2host-destination-ring4
 51:      13414          0          0          0     GIC-0 271 Edge      reo2host-destination-ring3
 52:      14596          0          0          0     GIC-0 268 Edge      reo2host-destination-ring2
 53:        908          0          0          0     GIC-0 267 Edge      reo2host-destination-ring1
 57:       1350          0          0          0     GIC-0 263 Edge      ppdu-end-interrupts-mac3
 58:          0          0          0          0     GIC-0 262 Edge      ppdu-end-interrupts-mac2
 59:      44944          0          0          0     GIC-0 261 Edge      ppdu-end-interrupts-mac1
 60:          1          0          0          0     GIC-0 260 Edge      rxdma2host-monitor-status-ring-mac3
 61:          0          0          0          0     GIC-0 256 Edge      rxdma2host-monitor-status-ring-mac2
 62:          1          0          0          0     GIC-0 255 Edge      rxdma2host-monitor-status-ring-mac1
 63:          3          0          0          0     GIC-0 235 Edge      host2rxdma-host-buf-ring-mac3
 64:          0          0          0          0     GIC-0 215 Edge      host2rxdma-host-buf-ring-mac2
 65:          1          0          0          0     GIC-0 212 Edge      host2rxdma-host-buf-ring-mac1
 66:          0          0          0          0     GIC-0 211 Edge      rxdma2host-destination-ring-mac3
 67:          0          0          0          0     GIC-0 210 Edge      rxdma2host-destination-ring-mac2
 68:          0          0          0          0     GIC-0 209 Edge      rxdma2host-destination-ring-mac1
 73:      10138          0          0          0     GIC-0 191 Edge      wbm2host-tx-completions-ring3
 74:       5377          0          0          0     GIC-0 190 Edge      wbm2host-tx-completions-ring2
 75:      15792          0          0          0     GIC-0 189 Edge      wbm2host-tx-completions-ring1
 77:   11836166          0          0          0     GIC-0 377 Level     edma_txcmpl
 78:          0          0          0          0     GIC-0 385 Level     edma_rxfill
 79:   17602596          0          0          0     GIC-0 393 Level     edma_rxdesc
 80:          0          0          0          0     GIC-0 376 Level     edma_misc
 81:          0          0          0          0       MSI   0 Edge      PCIe PME, aerdrv
 82:          0          0          0          0     smp2p   0 Edge      q6v5 fatal
 83:          1          0          0          0     smp2p   1 Edge      q6v5 ready
 84:          0          0          0          0     smp2p   2 Edge      q6v5 handover
 85:          0          0          0          0     smp2p   3 Edge      q6v5 stop
 86:          0          0          0          0   msmgpio  34 Edge      keys
 87:         31          0          0          0       MSI 524288 Edge      ath10k_pci
 88:         63          0          0          0     GIC-0 353 Edge      glink-native
IPI0:     98593     159529     149809     144011       Rescheduling interrupts
IPI1:      5707    7876083    2946458    3798672       Function call interrupts
IPI2:         0          0          0          0       CPU stop interrupts
IPI3:         0          0          0          0       CPU stop (for crash dump) interrupts
IPI4:         0          0          0          0       Timer broadcast interrupts
IPI5:      4849        176        243        218       IRQ work interrupts
IPI6:         0          0          0          0       CPU wake-up interrupts
Err:          0

Test #2:
Packet Stearing Enable; irqbalance Disable
See iperf3 --bidir option takes 100% of one core, but speed always ~930Mbits.
I couldn't see difference from test#1.
EDIT: Looking again at --bidir tests, here ksoftirqd/0 uses 107% core0 and in test#1 it only shows ~80%.

- - - - - - - - - - - - - - - - - - - - - - - - -
root@X2:~# service irqbalance status
inactive

**iperf3 -c 192.168.0.110 --bidir -t 30**
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval           Transfer     Bitrate         Retr
[  5][TX-C]   0.00-30.00  sec  3.25 GBytes   931 Mbits/sec    0             sender
[  5][TX-C]   0.00-30.00  sec  3.25 GBytes   930 Mbits/sec                  receiver
[  7][RX-C]   0.00-30.00  sec  3.26 GBytes   932 Mbits/sec    0             sender
[  7][RX-C]   0.00-30.00  sec  3.25 GBytes   931 Mbits/sec                  receiver
- - - - - - - - - - - - - - - - - - - - - - - - -
    0[|||||||||||||||||||||||||||||||||||||||||||||||100.0%] Tasks: 24, 8 thr, 78 kthr; 2 running
    1[||                                               1.9%] Load average: 0.67 0.25 0.09 
    2[|||||||                                         13.1%] Uptime: 00:14:28
    3[|                                                0.7%]
  Mem[||||||||||||||||||||||                      126M/408M]
  Swp[                                                0K/0K]

  PID USER       PRI  NI  VIRT   RES   SHR S CPU%-MEM%   TIME+  Command
   10 root        20   0     0     0     0 R 107.  0.0  1:56.26 ksoftirqd/0
   66 root        20   0     0     0     0 I  0.7  0.0  0:00.05 kworker/u8:2-events_power_efficient
 3475 root        20   0  1064   740   668 S  0.7  0.2  0:00.37 /usr/sbin/dropbear -F -P /var/run/dropbear.1.pid -p 192.
 3535 root        20   0  2068  1768  1080 R  0.7  0.4  0:04.09 htop
-------------------------------------------------------------------------------------------------------------
root@X2:~# cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3       
 11:      32558      35175      45261      21368     GIC-0  20 Level     arch_timer
 13:          0          0          0          0     GIC-0  39 Level     arch_mem_timer
 16:          2          0          0          0     GIC-0 354 Edge      smp2p
 17:          0          0          0          0     GIC-0 216 Level     4a9000.thermal-sensor
 18:          0          0          0          0     GIC-0 239 Level     bam_dma
 21:          0          0          0          0     GIC-0 270 Level     bam_dma
 22:          4          0          0          0     GIC-0 340 Level     msm_serial0
 23:      42231          0          0          0     GIC-0 178 Level     bam_dma
 24:          0          0          0          0     GIC-0  35 Edge      wdt_bark
 25:          0          0          0          0     GIC-0 357 Edge      q6v5 wdog
 29:          5          0          0          0     GIC-0 348 Edge      ce0
 30:          6          0          0          0     GIC-0 347 Edge      ce1
 31:         10          0          0          0     GIC-0 346 Edge      ce2
 32:          1          0          0          0     GIC-0 343 Edge      ce3
 34:          1          0          0          0     GIC-0 443 Edge      ce5
 36:          0          0          0          0     GIC-0  72 Edge      ce7
 38:          0          0          0          0     GIC-0 334 Edge      ce9
 39:          1          0          0          0     GIC-0 333 Edge      ce10
 40:          0          0          0          0     GIC-0  69 Edge      ce11
 47:          0          0          0          0     GIC-0 323 Edge      reo2ost-exception
 48:          0          0          0          0     GIC-0 322 Edge      wbm2host-rx-release
 49:          0          0          0          0     GIC-0 321 Edge      reo2host-status
 50:          0          0          0          0     GIC-0 320 Edge      reo2host-destination-ring4
 51:          0          0          0          0     GIC-0 271 Edge      reo2host-destination-ring3
 52:          0          0          0          0     GIC-0 268 Edge      reo2host-destination-ring2
 53:          0          0          0          0     GIC-0 267 Edge      reo2host-destination-ring1
 57:          1          0          0          0     GIC-0 263 Edge      ppdu-end-interrupts-mac3
 58:          0          0          0          0     GIC-0 262 Edge      ppdu-end-interrupts-mac2
 59:          1          0          0          0     GIC-0 261 Edge      ppdu-end-interrupts-mac1
 60:          1          0          0          0     GIC-0 260 Edge      rxdma2host-monitor-status-ring-mac3
 61:          0          0          0          0     GIC-0 256 Edge      rxdma2host-monitor-status-ring-mac2
 62:          1          0          0          0     GIC-0 255 Edge      rxdma2host-monitor-status-ring-mac1
 63:          3          0          0          0     GIC-0 235 Edge      host2rxdma-host-buf-ring-mac3
 64:          0          0          0          0     GIC-0 215 Edge      host2rxdma-host-buf-ring-mac2
 65:          1          0          0          0     GIC-0 212 Edge      host2rxdma-host-buf-ring-mac1
 66:          0          0          0          0     GIC-0 211 Edge      rxdma2host-destination-ring-mac3
 67:          0          0          0          0     GIC-0 210 Edge      rxdma2host-destination-ring-mac2
 68:          0          0          0          0     GIC-0 209 Edge      rxdma2host-destination-ring-mac1
 73:          0          0          0          0     GIC-0 191 Edge      wbm2host-tx-completions-ring3
 74:          0          0          0          0     GIC-0 190 Edge      wbm2host-tx-completions-ring2
 75:          0          0          0          0     GIC-0 189 Edge      wbm2host-tx-completions-ring1
 77:    8544235          0          0          0     GIC-0 377 Level     edma_txcmpl
 78:          0          0          0          0     GIC-0 385 Level     edma_rxfill
 79:   15310377          0          0          0     GIC-0 393 Level     edma_rxdesc
 80:          0          0          0          0     GIC-0 376 Level     edma_misc
 81:          0          0          0          0       MSI   0 Edge      PCIe PME, aerdrv
 82:          0          0          0          0     smp2p   0 Edge      q6v5 fatal
 83:          1          0          0          0     smp2p   1 Edge      q6v5 ready
 84:          0          0          0          0     smp2p   2 Edge      q6v5 handover
 85:          0          0          0          0     smp2p   3 Edge      q6v5 stop
 86:          0          0          0          0   msmgpio  34 Edge      keys
 87:         31          0          0          0       MSI 524288 Edge      ath10k_pci
 88:         63          0          0          0     GIC-0 353 Edge      glink-native
IPI0:     11404      15697      17646      18826       Rescheduling interrupts
IPI1:       746    3840260    6381339    1314527       Function call interrupts
IPI2:         0          0          0          0       CPU stop interrupts
IPI3:         0          0          0          0       CPU stop (for crash dump) interrupts
IPI4:         0          0          0          0       Timer broadcast interrupts
IPI5:       221         59         68         72       IRQ work interrupts
IPI6:         0          0          0          0       CPU wake-up interrupts
Err:          0

Test#3:
Packet Stearing Disable; irqbalance Disable
iperf3 --bidir option takes 100% of one core,
but now with Packet Stearing off, speed is not ~930Mbits.
I rebooted after disabling Packet Stearing and tested this 3 times, always same speeds.

mint@mint:~$ iperf3 -c 192.168.0.110 --bidir -t 60
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID][Role] Interval           Transfer     Bitrate         Retr
[  5][TX-C]   0.00-60.00  sec  6.46 GBytes   925 Mbits/sec  118             sender
[  5][TX-C]   0.00-60.00  sec  6.46 GBytes   924 Mbits/sec                  receiver
[  7][RX-C]   0.00-60.00  sec  3.11 GBytes   445 Mbits/sec  762             sender
[  7][RX-C]   0.00-60.00  sec  3.10 GBytes   444 Mbits/sec                  receiver

iperf Done.

Regarding the retries, I tried with several cables and kept a CAT6 2 meters cable.
In bidir test sometimes there are retries other times there are none, with same cable.

Note: Didn't test WIFI<->WAN because I don't have a fast card, I'm waiting for ax210 do be delivered.

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