Re: [dpdk-dev] [PATCH] doc: announce ABI change on ethdev

[Thomas Monjalon <thomas@monjalon.net>]

> > > 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 be superseded as well.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>

Applied, thanks