Re: [dpdk-dev] [PATCH v2 1/6] ethdev: add Tx preparation

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

On Mon, Sep 19, 2016 at 03:29:07PM +0000, Kulasek, TomaszX wrote:
> Hi Konstantin,
> 
> > -----Original Message-----
> > From: Ananyev, Konstantin
> > Sent: Monday, September 19, 2016 15:03
> > To: Kulasek, TomaszX <tomaszx.kulasek@intel.com>; dev@dpdk.org
> > Cc: jerin.jacob@caviumnetworks.com
> > Subject: RE: [dpdk-dev] [PATCH v2 1/6] ethdev: add Tx preparation
> > 
> > Hi Tomasz,
> > 
> > >
> 
> [...]
> 
> > > +
> > > +#ifdef RTE_ETHDEV_TX_PREP
> > 
> > Sorry for being a bit late on that discussion, but what the point of
> > having that config macro (RTE_ETHDEV_TX_PREP ) at all?
> > As I can see right now, if driver doesn't setup tx_pkt_prep, then nb_pkts
> > would be return anyway...
> > 
> > BTW, there is my another question - should it be that way?
> > Shouldn't we return 0 (and set rte_errno=ENOTSUP) here if dev->tx_pk_prep
> > == NULL?
> > 
> 
> It's an answer to the Jerin's request discussed here: http://dpdk.org/ml/archives/dev/2016-September/046437.html
> 
> When driver doesn't support tx_prep, default behavior is "we don't know requirements, so we have nothing to do here". It will simplify application logic and improve performance for these drivers, I think. Catching this error with every burst may be problematic.
> 
> As for RTE_ETHDEV_TX_PREP macro, suggested by Jerin in the same thread, I still don't think It's the best solution of the problem described by him. I have added it here for further discussion.
> 
> Jerin, have you something to add?

Nothing very specific to add here. I think, I have tried to share the rational in,
http://dpdk.org/ml/archives/dev/2016-September/046437.html

> 
> Tomasz.