How to Increase TX Queue Priority for LACP Packets

[Saad, Mark]

All
 Is there any way to make this change on other nic's like Intel ix and Solarflare sfxge ? I have seen similar issues on both with 12.1
mainly with solarflare nics.

---
Mark Saad
mark.saad at lucera.com


________________________________________
From: owner-freebsd-net at freebsd.org <owner-freebsd-net at freebsd.org> on behalf of Foster, Greg <gfoster at panasas.com>
Sent: Tuesday, June 16, 2020 3:56 PM
To: Navdeep Parhar
Cc: freebsd-net at freebsd.org
Subject: RE: How to Increase TX Queue Priority for LACP Packets

HI Navdeep,

Thanks for the information!  I've integrated the changes and will be testing more today.

We have seen the LACP port flapping under different scenarios, most we believe are
traffic/load based.

I did see the flapping unexpectedly when I just enabled LACP debug
(e.g., sysctl net.link.lagg.lacp.debug=1).     Is this a known problem?

Thanks
Greg

-----Original Message-----
From: Navdeep Parhar <nparhar at gmail.com> On Behalf Of Navdeep Parhar
Sent: Friday, June 12, 2020 7:51 PM
To: Foster, Greg <gfoster at panasas.com>
Cc: freebsd-net at freebsd.org
Subject: Re: How to Increase TX Queue Priority for LACP Packets

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

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