On 7/14/2022 3:07 PM, Ding, Xuan wrote:
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.
Isn't the intention of 'RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT' &
'RTE_ETH_RX_OFFLOAD_HEADER_SPLIT' are different?
Cc'ed Slava for more comment.
As far as I understand 'BUFFER_SPLIT' has a target to split package
based on size, to various size mempools, and it can split the payload as
well without caring the protocol headers.
Most probably practical usage is to split inner protocol, but protocol
not needed to be known by NIC, it can still split based on size.
Also as far as I can see mlx5 implemented the feature [1], contradicting
the claim in the commit log, again Slava can comment better. (Although I
don't see any PMD claim "Buffer Split on Rx" feature supported.)
[1]
Commit 9f209b59c8b0 ("net/mlx5: support Rx buffer split description")
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.
I can't see a v2 in patchwork, is a v2 sent? If so, may be something
went wrong.
