Network interface slow after reboot

[svengru]

I experience a strange network performance issue using 23.1.7 on a DEC850:

Setup:
DEC850 with latest firmware
Opnsense 23.1.7
10G link on ax.0. All HW offloading but VLAN HW offloading turned on.

I tweak all settings to archive 9.41 Gbits/sec from the DEC850 to my workstation. Very happy about that.

Now... the strange issue is that simply rebooting the DEC850 will bring that performance down to 3.xx Gbits/sec.
Even more strange, changing any network interface settings e.g. VLAN HW offloading from on to off and back to the original setting will restore the network performance back to 9.41 Gbits/sec.

Any pointers on how to debug?

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Debugged this some more:
Simply bringing the interface down with ifconfig and right back up again will resolve the issue until the next reboot.

Anybody else with an ax 10G Lan link that could try this?

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Last update:
Setup another DEC850 and setup a clean install using the defaults for the box.
The issue persists but seems to have no impact on firewall throughput. In other words, measuring each interface from the firewall shows the performance issue but testing firewall throughput shows zero performance issue.

Makes no sense to me.