Re: [dpdk-dev] [PATCH v11 1/6] ethdev: add Tx preparation

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2016-10-27 15:52, Ananyev, Konstantin:
> 
> > 
> > Hi Tomasz,
> > 
> > This is a major new function in the API and I still have some comments.
> > 
> > 2016-10-26 14:56, Tomasz Kulasek:
> > > --- a/config/common_base
> > > +++ b/config/common_base
> > > +CONFIG_RTE_ETHDEV_TX_PREP=y
> > 
> > We cannot enable it until it is implemented in every drivers.
> 
> Not sure why?
> If tx_pkt_prep == NULL, then rte_eth_tx_prep() would just act as noop.
> Right now it is not mandatory for the PMD to implement it.

If it is not implemented, the application must do the preparation by itself.
>From patch 6:
"
Removed pseudo header calculation for udp/tcp/tso packets from
application and used Tx preparation API for packet preparation and
verification.
"
So how does it behave with other drivers?

> > >  struct rte_eth_dev {
> > >  	eth_rx_burst_t rx_pkt_burst; /**< Pointer to PMD receive function. */
> > >  	eth_tx_burst_t tx_pkt_burst; /**< Pointer to PMD transmit function. */
> > > +	eth_tx_prep_t tx_pkt_prep; /**< Pointer to PMD transmit prepare function. */
> > >  	struct rte_eth_dev_data *data;  /**< Pointer to device data */
> > >  	const struct eth_driver *driver;/**< Driver for this device */
> > >  	const struct eth_dev_ops *dev_ops; /**< Functions exported by PMD */
> > 
> > Could you confirm why tx_pkt_prep is not in dev_ops?
> > I guess we want to have several implementations?
> 
> Yes, it depends on configuration options, same as tx_pkt_burst.
> 
> > 
> > Shouldn't we have a const struct control_dev_ops and a struct datapath_dev_ops?
> 
> That's probably a good idea, but I suppose it is out of scope for that patch.

No it's not out of scope.
It answers to the question "why is it added in this structure and not dev_ops".
We won't do this change when nothing else is changed in the struct.