Hi, > -----Original Message----- > From: Thomas Monjalon <tho...@monjalon.net> > Sent: Thursday, July 14, 2022 9:25 PM > To: Ding, Xuan <xuan.d...@intel.com>; andrew.rybche...@oktetlabs.ru; > ferruh.yi...@xilinx.com > Cc: m...@ashroe.eu; dev@dpdk.org; step...@networkplumber.org; > m...@smartsharesystems.com; dev@dpdk.org; Zhang, Qi Z > <qi.z.zh...@intel.com>; asek...@marvell.com; pbhagavat...@marvell.com; > gr...@u256.net > Subject: Re: [PATCH] doc: announce header split deprecation > > 14/07/2022 14:54, Ding, Xuan: > > Hi, > > > > From: Thomas Monjalon <tho...@monjalon.net> > > > 14/07/2022 07:50, Ding, Xuan: > > > > From: Thomas Monjalon <tho...@monjalon.net> > > > > > 23/05/2022 16:20, xuan.d...@intel.com: > > > > > > From: Xuan Ding <xuan.d...@intel.com> > > > > > > > > > > > > RTE_ETH_RX_OFFLOAD_HEADER_SPLIT offload was introduced > some > > > time > > > > > ago > > > > > > to substitute bit-field header_split in struct rte_eth_rxmode. > > > > > > It allows to enable header split offload with the header size > > > > > > controlled using split_hdr_size in the same structure. > > > > > > > > > > > > Right now, no single PMD actually supports > > > > > > RTE_ETH_RX_OFFLOAD_HEADER_SPLIT with above definition. Many > > > > > > examples and test apps initialize the field to 0 explicitly. > > > > > > The most of drivers simply ignore split_hdr_size since the > > > > > > offload is not advertised, but > > > > > some double-check that its value is 0. > > > > > > > > > > > > So the RTE_ETH_RX_OFFLOAD_HEADER_SPLIT and split_header_size > > > field > > > > > > will be removed in DPDK 22.11. > > > > > > > > > > > > Signed-off-by: Xuan Ding <xuan.d...@intel.com> > > > > > > --- > > > > > > doc/guides/rel_notes/deprecation.rst | 4 ++++ > > > > > > 1 file changed, 4 insertions(+) > > > > > > > > > > > > diff --git a/doc/guides/rel_notes/deprecation.rst > > > > > > b/doc/guides/rel_notes/deprecation.rst > > > > > > index 4e5b23c53d..b8114f29ed 100644 > > > > > > --- a/doc/guides/rel_notes/deprecation.rst > > > > > > +++ b/doc/guides/rel_notes/deprecation.rst > > > > > > @@ -125,3 +125,7 @@ Deprecation Notices > > > > > > applications should be updated to use the ``dmadev`` library > instead, > > > > > > with the underlying HW-functionality being provided by the > > > > > > ``ioat`` > or > > > > > > ``idxd`` dma drivers > > > > > > + > > > > > > +* ethdev: After bit-field header split was removed, the > > > > > > +``RTE_ETH_RX_OFFLOAD_HEADER_SPLIT`` > > > > > > +offload and the ``split_hdr_size`` field in structure > > > > > > +``rte_eth_rxmode`` to enable header split offload are not > > > > > > +supported in any > > > > > PMDs. They will be removed in DPDK 22.11. > > > > > > > > > > It would have been good to talk about rte_eth_rxseg_split which > > > > > is similar and configured per-queue. > > > > > > > > Thanks for your suggestion. > > > > > > > > But I'm a little confused, are you referring that I need to > > > > involve protocol > > > based buffer split? > > > > About the deprecation of header split, I haven't realized its > > > > connection to > > > rte_eth_rxseg_split. > > > > > > What??? > > > In old versions of your patch "ethdev: introduce protocol type based > > > header split" > > > you wrote: > > > " > > > A new proto field is introduced in the rte_eth_rxseg_split structure > > > reserved field to specify header protocol type. > > > With Rx offload flag RTE_ETH_RX_OFFLOAD_HEADER_SPLIT enabled and > > > protocol type configured, PMD will split the ingress packets into > > > two separate regions. > > > " > > > > It has a long history... > > It was corrected in v4 that RTE_ETH_RX_OFFLOAD_HEADER_SPLIT is used to > > enable header split offload with the header size controlled using > "split_hdr_size". > > But no single PMD actually supports RTE_ETH_RX_OFFLOAD_HEADER_SPLIT > for this purpose. > > So we finally decide to deprecate this flag. > > > > http://patchwork.dpdk.org/project/dpdk/patch/20220402104109.472078- > 2-w > > enxuanx...@intel.com/ > > > > In following series, I use RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT instead. It > > is for multi-segments packet split. And it still needs a "proto_hdr" field > > in > rte_eth_rxmode to configure split location. > > I know this history because I was the one asking you to deprecate this. > But it seems you didn't get the big picture. > > > > > Currently there are 2 acks, add more PMD maintainers to help > > > > review this deprecation notice for header split, thanks a lot! > > > > > > I cannot say my feeling strong enough. > > > > So IMO the deprecation for header split is not relevant with buffer split. > > But > we can still clean the code. > > Hope it make things clearer. > > They are almost the same features. > So when deprecating one, it is important to mention what remains. > If needed RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT can still be used and it is > configured per-queue, while RTE_ETH_RX_OFFLOAD_HEADER_SPLIT was > configurable per-port.
Thanks for your clarification. It's clearer now. I was trying to figure out the whole history of header split, seems it is not enough. > > Andrew, Ferruh, do you agree to improve this deprecation notice by adding > above information? Agree. It is better to point out the remaining per queue rx offload RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT for splitting packets. Please see v2 after I add more header split background. Regards, Xuan >
