Re: [PATCH] net: fec: select queue depending on VLAN priority

[Stefan Agner <stefan@agner.ch>]

On 2017-05-09 06:39, David Miller wrote:
> From: Stefan Agner <stefan@agner.ch>
> Date: Mon,  8 May 2017 22:37:08 -0700
> 
>> Since the addition of the multi queue code with commit 59d0f7465644
>> ("net: fec: init multi queue date structure") the queue selection
>> has been handelt by the default transmit queue selection
>> implementation which tries to evenly distribute the traffic across
>> all available queues. This selection presumes that the queues are
>> using an equal priority, however, the queues 1 and 2 are actually
>> of higher priority (the classification of the queues is enabled in
>> fec_enet_enable_ring).
>>
>> This can lead to net scheduler warnings and continuous TX ring
>> dumps when exercising the system with iperf.
>>
>> Use only queue 0 for all common traffic (no VLAN and P802.1p
>> priority 0 and 1) and route level 2-7 through queue 1 and 2.
>>
>> Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
>> Fixes: 59d0f7465644 ("net: fec: init multi queue date structure")
> 
> If the queues are used for prioritization, and it does not have
> multiple normal priority level queues, multiqueue is not what the
> driver should have implemented.

As Andy mentioned, there is also a round-robin mode. I'll try that.

What would be the proper way to use the prioritized queues?

--
Stefan