Re: [PATCH net-next 0/2] net: stmmac: add EthType Rx Frame steering

On Fri, 10 Dec 2021 13:57:30 +0200 Vladimir Oltean wrote:

Is it the canonical approach to perform flow steering via tc-flower hw_tc,
as opposed to ethtool --config-nfc? My understanding from reading the
documentation is that tc-flower hw_tc only selects the hardware traffic
class for a packet, and that this has to do with prioritization
(although the concept in itself is a bit ill-defined as far as I
understand it, how does it relate to things like offloaded skbedit priority?).
But selecting a traffic class, in itself, doesn't (directly or
necessarily) select a ring per se, as ethtool does? Just like ethtool
doesn't select packet priority, just RX queue. When the RX queue
priority is configurable (see the "snps,priority" device tree property
in stmmac_mtl_setup) and more RX queues have the same priority, I'm not
sure what hw_tc is supposed to do in terms of RX queue selection?

You didn't mention the mqprio, but I think that's the piece that maps
TCs to queue pairs. You can have multiple queues in a TC.

Obviously that's still pretty weird what the flow rules should select
is an RSS context. mqprio is a qdisc, which means Tx, not Rx.

Adding Amritha who I believe added the concept of selecting Rx queues
via hw_tc. Can you comment?