Re: [dpdk-dev] [PATCH v7 00/14] add hairpin feature

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 10/30/2019 11:53 PM, Ori Kam wrote:
> This patch set implements the hairpin feature.
> The hairpin feature was introduced in 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.
> 
> The advantages of using the queue approch:
> 1. More control for the application. queue depth (the memory size that
> should be used).
> 2. Enable QoS. QoS is normaly a parametr of queue, so in this approch it
> will be easy to integrate with such system.
> 3. Native integression with the rte flow API. Just setting the target
> queue/rss to hairpin queue, will result that the traffic will be routed
> to the hairpin queue.
> 4. Enable queue offloading.
> 
> Each hairpin Rxq can be connected Txq / number of Txqs which can belong to a
> different ports assuming the PMD supports it. The same goes the other
> way each hairpin Txq can be connected to one or more Rxqs.
> This is the reason that both the Txq setup and Rxq setup are getting the
> hairpin configuration structure.
> 
> From PMD prespctive the number of Rxq/Txq is the total of standard
> queues + hairpin queues.
> 
> To configure hairpin queue the user should call
> rte_eth_rx_hairpin_queue_setup / rte_eth_tx_hairpin_queue_setup insteed
> of the normal queue setup functions.
> 
> The hairpin queues are not part of the normal RSS functiosn.
> 
> To use the queues the user simply create a flow that points to RSS/queue
> actions that are hairpin queues.
> The reason for selecting 2 new functions for hairpin queue setup are:
> 1. avoid API break.
> 2. avoid extra and unused parameters.
> 
> 
> 
> [1] https://inbox.dpdk.org/dev/1565703468-55617-1-git-send-email-orika@mellanox.com/
> 
> Cc: wenzhuo.lu@intel.com
> Cc: bernard.iremonger@intel.com
> Cc: thomas@monjalon.net
> Cc: ferruh.yigit@intel.com
> Cc: arybchenko@solarflare.com
> Cc: viacheslavo@mellanox.com
> 
> ------
> V7:
>  - all changes are in patch 2: ethdev: add support for hairpin queue
>    - Move is_rx/tx_hairpin_queue to ethdev.c and ethdev.h also remove the inline.
>    - change checks for max number of hairpin queues.
>    - modify log messages.
> 
> V6:
>  - add missing include in nfb driver.
>  - change comparing of rte_eth_dev_is_tx_hairpin_queue /
>    rte_eth_dev_is_rx_hairpin_queue to boolean operator.
>  - split the doc patch to the relevant patches.
> 
> V5:
>  - modify log messages to be more distinct.
>  - set that log message will be in the same line even if > 80.
>  - change peer_n to peer_count.
>  - add functions to get if queue is hairpin queue.
> 
> V4:
>  - update according to comments from ML.
> 
> V3:
>  - update according to comments from ML.
> 
> V2:
>  - update according to comments from ML.
> 
> 
> 
> 
> Ori Kam (14):
>   ethdev: move queue state defines to private file
>   ethdev: add support for hairpin queue
>   net/mlx5: query hca hairpin capabilities
>   net/mlx5: support Rx hairpin queues
>   net/mlx5: prepare txq to work with different types
>   net/mlx5: support Tx hairpin queues
>   net/mlx5: add get hairpin capabilities
>   app/testpmd: add hairpin support
>   net/mlx5: add hairpin binding function
>   net/mlx5: add support for hairpin hrxq
>   net/mlx5: add internal tag item and action
>   net/mlx5: add id generation function
>   net/mlx5: add default flows for hairpin
>   net/mlx5: split hairpin flows

Series applied to dpdk-next-net/master, thanks.

Except testpmd patch (8/14), it can be worked on separately.