Re: [dpdk-dev] [PATCH v12 1/6] ethdev: add Tx preparation

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

Please, a reply to this question would be greatly appreciated.

2016-11-28 11:54, Thomas Monjalon:
> Hi,
> 
> 2016-11-23 18:36, Tomasz Kulasek:
> > --- a/config/common_base
> > +++ b/config/common_base
> > @@ -120,6 +120,7 @@ CONFIG_RTE_MAX_QUEUES_PER_PORT=1024
> >  CONFIG_RTE_LIBRTE_IEEE1588=n
> >  CONFIG_RTE_ETHDEV_QUEUE_STAT_CNTRS=16
> >  CONFIG_RTE_ETHDEV_RXTX_CALLBACKS=y
> > +CONFIG_RTE_ETHDEV_TX_PREPARE=y
> 
> Please, remind me why is there a configuration here.
> It should be the responsibility of the application to call tx_prepare
> or not. If the application choose to use this new API but it is
> disabled, then the packets won't be prepared and there is no error code:
> 
> > +#else
> > +
> > +static inline uint16_t
> > +rte_eth_tx_prepare(__rte_unused uint8_t port_id, __rte_unused uint16_t queue_id,
> > +               __rte_unused struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
> > +{
> > +       return nb_pkts;
> > +}
> > +
> > +#endif
> 
> So the application is not aware of the issue and it will not use
> any fallback.