Re: [PATCH] doc: announce ABI change on ethdev

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

-----Original Message-----
> Date: Tue, 9 May 2017 15:40:04 +0200
> From: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> To: Shahaf Shuler <shahafs@mellanox.com>, Konstantin Ananyev
>  <konstantin.ananyev@intel.com>, Olivier Matz <olivier.matz@6wind.com>,
>  Tomasz Kulasek <tomaszx.kulasek@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] doc: announce ABI change on ethdev
> 
> On Mon, May 01, 2017 at 09:58:12AM +0300, Shahaf Shuler wrote:
> > This is an ABI change notice for DPDK 17.08 in librte_ether
> > about changes in rte_eth_txmode structure.
> > 
> > Currently Tx offloads are enabled by default, and can be disabled
> > using ETH_TXQ_FLAGS_NO* flags. This behaviour is not consistent with
> > the Rx side where the Rx offloads are disabled by default and enabled
> > according to bit field in rte_eth_rxmode structure.
> > 
> > The proposal is to disable the Tx offloads by default, and provide
> > a way for the application to enable them in rte_eth_txmode structure.
> > Besides of making the Tx configuration API more consistent for
> > applications, PMDs will be able to provide a better out of the
> > box performance.
> > Finally, as part of the work, the ETH_TXQ_FLAGS_NO* will
> > be superseded as well.
> > 
> > Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>
> 
> Basically, TX mbuf flags like TSO and checksum offloads won't have to be
> honored by PMDs unless applications request them first while configuring the
> device, just like RX offloads.
> 
> Considering more and more TX offloads will be added over time, I do not
> think expecting them all to be enabled by default is sane. There will always
> be an associated software cost in PMDs, and this solution allows
> applications to selectively enable them as needed for maximum performance.
> 
> Konstantin/Olivier/Tomasz, I do not want to resume the thread about
> tx_prepare(), however this could provide an alternative means to benefit
> from improved performance when applications do not need TSO (or any other
> offload for that matter), while adding consistency to device configuration.
> 
> What's your opinion?
> 
> In any case I'm fine with this change:
> 
> Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>

Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>