Re: [dpdk-dev] [PATCH] net/i40e: add Tx preparation for vector data path

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> 
> On Wed, Mar 31, 2021 at 11:17 AM Leyi Rong <leyi.rong@intel.com> wrote:
> >
> > Fill up dev->tx_pkt_prepare to i40e_pkt_prepare when on vector and simple
> > data path selection, as the sanity check is needed ideally.
> >
> > Signed-off-by: Leyi Rong <leyi.rong@intel.com>
> > ---
> >  drivers/net/i40e/i40e_rxtx.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
> > index 61cb204be2..b3d7765e3b 100644
> > --- a/drivers/net/i40e/i40e_rxtx.c
> > +++ b/drivers/net/i40e/i40e_rxtx.c
> > @@ -3412,7 +3412,7 @@ i40e_set_tx_function(struct rte_eth_dev *dev)
> >                         PMD_INIT_LOG(DEBUG, "Simple tx finally be used.");
> >                         dev->tx_pkt_burst = i40e_xmit_pkts_simple;
> >                 }
> > -               dev->tx_pkt_prepare = NULL;
> > +               dev->tx_pkt_prepare = i40e_prep_pkts;
> >         } else {
> >                 PMD_INIT_LOG(DEBUG, "Xmit tx finally be used.");
> >                 dev->tx_pkt_burst = i40e_xmit_pkts;
> 
> I find this a bit surprising to set this op at two different locations.
> Why not simply leave the value set in i40e_ethdev.c?
> 

Actually I wonder should we set dev->tx_pkt_prepare to  point to i40e_prep_pkts()
for simple TX path?
As I remember, simple TX path doesn't support neither multi-segment packets, 
neither TX offloads. 
While i40e_prep_pkts() assumes that selected tx_burst() supports all that.
If you don't want to keep dev->tx_pkt_prepare==NULL for simple TX path,
why not create  a new one: i40e_simple_prep_pkts() or so?

Konstantin