[dpdk-dev] [pbhagavatula@caviumnetworks.com: Re: [PATCH 2/4] eventdev: add caps API and PMD callbacks for eth Tx adapter]

[Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>]

Hi Nikhil,

On Mon, Jul 16, 2018 at 11:25:45AM +0530, Rao, Nikhil wrote:
> On 7/10/2018 4:26 PM, Pavan Nikhilesh wrote:
> > +int __rte_experimental
> > +rte_event_eth_tx_adapter_caps_get(uint8_t dev_id, uint32_t *caps)
> > +{
> > The caps get API needs to be similar to rx adapter caps get i.e. it needs to
> > have the eth_port_id as a parameter so that the underlying event dev driver can
> > expose INTERNAL PORT capability as not all ethdev drivers have the capability
> > to interact with the eventdevs internal port.
> >
> > rte_event_eth_tx_adapter_caps_get(uint8_t dev_id, uint16_t eth_port_id,
> >                       uint32_t *caps);
> Hi Pavan,
>
> Is querying the INTERNAL PORT on a per ethdev basis useful to the
> application ?

If an application chooses to use 2 ports one with INTERNAL PORT capability and
one _without_ it then it would be useful to have per ethdev based
classification similar to Rx adapter. The application can classify events based
on event type RTE_EVENT_TYPE_ETHDEV & RTE_EVENT_TYPE_ETH_RX_ADAPTER to
segregate between INTERNAL & NON-INTERNAL port at ingress side and enqueue it
to either rte_event_eth_tx_adapter_enqueue or to the SINGLE link queue
respectively.

Also, I dont think eventdev should iterate over all probed ethdevs and give
the overall caps as an application might want only a specific ethdev to be
connected to the event tx adapter.

>
> For e.g., the txa_init() function in the adapter implementation can only
> decide to use the internal port if it is supported for all ethdevs,
> hence I left that upto the eventdev PMD to decide - i.e., it could
> iterate across txa->dev_count eth devices to make that determination.
> For caps in general, I agree it makes sense to pass in the ethdev, but
> the INTERNAL PORT didn't seem useful on a per ethdev basis.
>
> We could also replace caps_get with something like a
> rte_event_eth_tx_adapter_internal_port_check(dev_id) and add a per
> ethdev caps if needed later.
>
> Thanks,
> Nikhil

Thanks,
Pavan.