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

Kulasek, TomaszX tomaszx.kulasek at intel.com
Mon Sep 19 17:29:07 CEST 2016


Hi Konstantin,

> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Monday, September 19, 2016 15:03
> To: Kulasek, TomaszX <tomaszx.kulasek at intel.com>; dev at dpdk.org
> Cc: jerin.jacob at 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?

Tomasz.


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