[dpdk-users] mlx5 flow MARK action does not work with RSS

Shahaf Shuler shahafs at mellanox.com
Sun Feb 3 13:44:54 CET 2019


Thursday, January 31, 2019 6:41 PM, Tom Barbette:
> Subject: Re: [dpdk-users] mlx5 flow MARK action does not work with RSS
> 
> Le 31/01/2019 à 15:04, Shahaf Shuler a écrit :
> > What is the functionally you seek? It will much help to propose a solution.
> 
> 
> What I'd like is to mark some packets. Eg ARP packets with 1, ICMP PING with
> 2, IP dst port 80 with 3, etc.
> 
> But I'd like the packets to follow the normal behavior except from that.
> My default behavior would be to use RSS to dispatch packets among a set of
> queues.
> 
> In the current scheme, I must set a specific "fate" action for each flow, like
> QUEUE or RSS.
> Of course the list of flows is dynamically generated, and it is complicated to
> change QUEUE/RSS according to the flow type. I would like to say "mark
> packets, then do as the NIC would normally do". That's why I imagine a
> "default" action.

There is a default RSS hashing. For example, for IP dst port 80 w/ mark 3 and 4 rxqs do:
testpmd> flow create 0 ingress pattern eth / ipv4 / udp dst is 80 / end actions mark id 3 / rss queues 0 1 2 3 end / end

This will tell the PMD to do RSS action to all queues and it will use the default RSS defined on the port. Which means you will get the exact same behavior like the default action.
You can append this RSS action to every rule you create.

There is one issue w/ ARP. Mellanox devices cannot do RSS on the ether only packets. As such, RSS action on ARP packet will fail. 
So for Ether only packet you will have to use the queue action. The "default" behavior will be go to queue index 0. 

> 
> 
> Thanks,
> Tom


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