[RFC 2/5] ethdev: introduce the affinity field in Tx queue API

[Jiawei(Jonny) Wang]

Hi,


> 
> 21/12/2022 11:29, Jiawei Wang:
> > For the multiple hardware ports connect to a single DPDK port
> > (mhpsdp), the previous patch introduces the new rte flow item to match
> > the port affinity of the received packets.
> >
> > This patch adds the tx_affinity setting in Tx queue API, the affinity
> > value reflects packets be sent to which hardware port.
> 
> I think "affinity" means we would like packet to be sent on a specific hardware
> port, but it is not mandatory.
> Is it the meaning you want? Or should it be a mandatory port?
> 

Right, it's optional setting not mandatory.

> > Adds the new tx_affinity field into the padding hole of rte_eth_txconf
> > structure, the size of rte_eth_txconf keeps the same. Adds a suppress
> > type for structure change in the ABI check file.
> >
> > This patch adds the testpmd command line:
> > testpmd> port config (port_id) txq (queue_id) affinity (value)
> >
> > For example, there're two hardware ports connects to a single DPDK
> 
> connects -> connected
> 

OK, will fix in next version.

> > port (port id 0), and affinity 1 stood for hard port 1 and affinity
> > 2 stood for hardware port 2, used the below command to config tx
> > affinity for each TxQ:
> > 	port config 0 txq 0 affinity 1
> > 	port config 0 txq 1 affinity 1
> > 	port config 0 txq 2 affinity 2
> > 	port config 0 txq 3 affinity 2
> >
> > These commands config the TxQ index 0 and TxQ index 1 with affinity 1,
> > uses TxQ 0 or TxQ 1 send packets, these packets will be sent from the
> > hardware port 1, and similar with hardware port 2 if sending packets
> > with TxQ 2 or TxQ 3.
> 
> [...]
> > @@ -212,6 +212,10 @@ API Changes
> > +* ethdev: added a new field:
> > +
> > +  - Tx affinity per-queue ``rte_eth_txconf.tx_affinity``
> 
> Adding a new field is not an API change because existing applications don't
> need to update their code if they don't care this new field.
> I think you can remove this note.
> 

OK, will remove in next version.

> > --- a/lib/ethdev/rte_ethdev.h
> > +++ b/lib/ethdev/rte_ethdev.h
> > @@ -1138,6 +1138,7 @@ struct rte_eth_txconf {
> >  				      less free descriptors than this value. */
> >
> >  	uint8_t tx_deferred_start; /**< Do not start queue with
> > rte_eth_dev_start(). */
> > +	uint8_t tx_affinity; /**< Drives the setting of affinity per-queue.
> > +*/
> 
> Why "Drives"? It is the setting, right?
> rte_eth_txconf is per-queue so no need to repeat.
> I think a good comment here would be to mention it is a physical port index for
> mhpsdp.
> Another good comment would be to specify how ports are numbered.
> 

OK, will update the comment for this new setting.

Thanks.