[PATCH v6] ethdev: introduce available Rx descriptors threshold

[Thomas Monjalon]

08/06/2022 18:35, Andrew Rybchenko:
> From: Spike Du <spiked at nvidia.com>
> 
> A new event RTE_ETH_EVENT_RX_AVAIL_THRESH should be generated by HW
> when number of available descriptors in Rx queue goes below the
> threshold.
> 
> The threshold is defined as a percentage of an Rx queue size with valid
> values from 0 to 99 (inclusive). Zero (default) value disables it.
> 
> There is no capability reporting for the feature. Application should
> simply try to set required threshold value and handle result.
> 
> Add testpmd commands to control the threshold:
>   set port <port_id> rxq <rxq_id> avail_thresh <avail_thresh_num>
> 
> Signed-off-by: Spike Du <spiked at nvidia.com>
> Signed-off-by: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>
> ---
> v6:
>     - try to make descriptor shorter and more useful
>     - refine terminology to use "available descriptors threshold"
>       everywhere (plural "descriptors")
>     - fix ethdev API documenation
>     - define negative return values
>     - define rules to convert percentage to descriptors number
>       in drivers
>     - avoid extra checks in testpmd helper to allow ethdev API
>       to do its job
>     - minor fixes in testpmd variables naming
>     - fix testpmd help to be human oriented
>     - update testpmd users guide
>     - add release notes

What a (more than) review work, thanks a lot for this v6!

Acked-by: Thomas Monjalon <thomas at monjalon.net>

With a few minor arrangements,
applied, thanks.