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Date:      Fri, 12 Jun 2020 19:50:44 -0700
From:      Navdeep Parhar <np@FreeBSD.org>
To:        "Foster, Greg" <gfoster@panasas.com>
Cc:        "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>
Subject:   Re: How to Increase TX Queue Priority for LACP Packets
Message-ID:  <20200613025031.GA34653@x270>
In-Reply-To: <BYAPR08MB6038FF630C3C8EEC4F11862BB4810@BYAPR08MB6038.namprd08.prod.outlook.com>

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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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