[dpdk-dev] [PATCH v3 01/39] examples/l2fwd: convert to new ethdev offloads API

[Shahaf Shuler]

Monday, January 15, 2018 1:34 PM, Ferruh Yigit:
> >> Currently no PMD seems implemented it.
> >
> > Sure,
> >
> > FAST_FREE offload is the logical AND between the old txqflags of:
> > ETH_TXQ_FLAGS_NOREFCOUNT
> > ETH_TXQ_FLAGS_NOMULTMEM
> >
> > The offload is just a performance optimization. As specified in the
> documentation [1] it enables the PMDs to further optimize the data path
> given the guarantees from the application.
> > Not having it means possible performance degradation for some PMD
> which rely on it.
> >
> > There is no PMD which implement it yet since not all PMDs moved to the
> new offloads API. However this flag is tested and translated into txqflags as
> part of rte_eth_convert_txq_offloads function.
> > Relevant PMDs for this offload will be: sfc, thunderx and i40e.
> 
> Thank you for clarification, I am OK to have it.
> 
> But since currently no PMD provide "DEV_TX_OFFLOAD_MBUF_FAST_FREE"
> capability, and default txq_flags is overwritten, some PMDs lost this
> optimization until they implement new capability, right?

Yes this is correct, a good motivation to convert :). 
From the examples and testpmd part everything is ready. Just need for the PMD to report back the capability to have this offload.