How to Increase TX Queue Priority for LACP Packets

[Navdeep Parhar]

On Fri, Jun 12, 2020 at 11:47:41PM +0000, Foster, Greg wrote:
> FreeBSD Networkers,
> 
> We are seeing LACP port flapping on our FreeBSD 10.4/12.1 systems under
> different conditions.
> 
> Can someone explain or point me to the information on how to queue the
> LACP packets to a higher priority queue ?
> 
> We are using the Chelsio T580-LP-CR adapter/cxgbe driver.  The Cheslio
> NICs have 8 TX/RX queues each, but I don't know how to explicitly put
> the LACP packets in the higher priority TX queue.
>
> I've read about PF/ALTQ and think this may be overkill our needs, and
> was wondering if there was a simpler method.

This is cxgbe specific but that's what you're using so it'll do.

Add "hw.cxgbe.rsrv_noflowq=1" to your /boot/loader.conf.  That reserves
one tx queue for non-RSS traffic (like ARP, LACP).  You might also want
to increase the number of tx queues to compensate for the one that's now
reserved.  Use "hw.cxgbe.ntxq=9" for that.  The ntxq knob might be
different on 10.4 but the man page matching the driver should have its
exact name.

Regards,
Navdeep