[dpdk-dev] [RFC] ethdev: support hairpin queue

Stephen Hemminger stephen at networkplumber.org
Tue Aug 13 17:46:19 CEST 2019

On Tue, 13 Aug 2019 13:37:48 +0000
Ori Kam <orika at mellanox.com> wrote:

> This RFC replaces RFC[1].
> The hairpin feature (different name can be forward) acts as "bump on the wire",
> meaning that a packet that is received from the wire can be modified using
> offloaded action and then sent back to the wire without application intervention
> which save CPU cycles.
> The hairpin is the inverse function of loopback in which application
> sends a packet then it is received again by the
> application without being sent to the wire.
> The hairpin can be used by a number of different NVF, for example load
> balancer, gateway and so on.
> As can be seen from the hairpin description, hairpin is basically RX queue
> connected to TX queue.
> During the design phase I was thinking of two ways to implement this
> feature the first one is adding a new rte flow action. and the second
> one is create a special kind of queue.

Life would be easier for users if the hairpin was an attribute
of queue configuration, not a separate API call.

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