Re: [dpdk-stable] [PATCH 19.11.6 00/13] backport for 19.11.6

[Luca Boccassi <bluca@debian.org>]

On Fri, 2020-11-13 at 21:36 +0800, Lijun Ou wrote:
> Hi, Luca Boccassi
> His series are backport for 19.11.6 about hns3 PMD driver
> I also noticed that you gave Hu Wei a suggestion on the 19.11.4
> backport. You did not recommend adding new features. I reselected
> the TSO and some performance optimization patch request backports.
> The reason I do this is that I think TSO is also a performance
> optimization point, including other fixes. In addition, if TSO
> is not integrated, the bug fixes of the cksum may not be integrated,
> which will cause the stability of the cksum function.
> 
> Chengchang Tang (5):
>   net/hns3: support promiscuous and allmulticast mode for VF
>   net/hns3: decrease non-nearby memory access in Rx
>   net/hns3: cleanup duplicated code on processing TSO in Tx
>   net/hns3: fix Tx checksum outer header prepare
>   net/hns3: fix Tx checksum with fixed header length
> 
> Hongbo Zheng (1):
>   net/hns3: check TSO segment size during Tx
> 
> Lijun Ou (2):
>   net/hns3: support TSO
>   net/hns3: report Tx descriptor segment limitations
> 
> Wei Hu (Xavier) (5):
>   net/hns3: fix reassembling multiple segment packets in Tx
>   net/hns3: fix inserted VLAN tag position in Tx
>   net/hns3: report Rx drop packets enable configuration
>   net/hns3: report Rx free threshold
>   net/hns3: reduce address calculation in Rx
> 
>  doc/guides/nics/features/hns3.ini    |   1 +
>  doc/guides/nics/features/hns3_vf.ini |   3 +
>  doc/guides/nics/hns3.rst             |   1 +
>  drivers/net/hns3/hns3_ethdev.c       |  38 +-
>  drivers/net/hns3/hns3_ethdev.h       |  37 +-
>  drivers/net/hns3/hns3_ethdev_vf.c    | 134 ++++++-
>  drivers/net/hns3/hns3_mbx.c          |  23 ++
>  drivers/net/hns3/hns3_mbx.h          |   2 +
>  drivers/net/hns3/hns3_rxtx.c         | 666 ++++++++++++++++++++++++-----------
>  drivers/net/hns3/hns3_rxtx.h         |  31 +-
>  10 files changed, 720 insertions(+), 216 deletions(-)

Hi,

I discussed this proposal with other maintainers, and I'm afraid the
original answer still stands - we feel backporting an entire new
offload is too much for the scope of an LTS release.

While sometimes we do allow for some featurettes to be backported, in
the form of a new #define or such small changes, there was consensus
that a 936 lines diff is too much churn for what is expected from a
stable release, which is stability. The risk of introducing new bugs,
especially in face of the fact that we never had regression tests
coverage for the hns3 PMD for LTSes before, is too high.

The 20.05/20.08 releases are ABI compatible with 19.11, so if there's
an urgent need for this feature in users of the hns3 PMD, one of those
can be used instead. Some other companies also maintain downstream
trees of the LTSes with invasive changes to their PMDs, that are deemed
too risky for the upstream tree, so that's another option available to
you.

Sorry!

-- 
Kind regards,
Luca Boccassi