RE: [PATCH v10 net-next 00/15] AccECN protocol case handling series

-----Original Message-----
From: Neal Cardwell <ncardwell@google.com>
Sent: Wednesday, January 21, 2026 10:07 PM
To: Jakub Kicinski <kuba@kernel.org>
Cc: Chia-Yu Chang (Nokia) <redacted>; pabeni@redhat.com; edumazet@google.com; parav@nvidia.com; linux-doc@vger.kernel.org; corbet@lwn.net; horms@kernel.org; dsahern@kernel.org; kuniyu@google.com; bpf@vger.kernel.org; netdev@vger.kernel.org; dave.taht@gmail.com; jhs@mojatatu.com; stephen@networkplumber.org; xiyou.wangcong@gmail.com; jiri@resnulli.us; davem@davemloft.net; andrew+netdev@lunn.ch; donald.hunter@gmail.com; ast@fiberby.net; liuhangbin@gmail.com; shuah@kernel.org; linux-kselftest@vger.kernel.org; ij@kernel.org; Koen De Schepper (Nokia) <redacted>; g.white@cablelabs.com; ingemar.s.johansson@ericsson.com; mirja.kuehlewind@ericsson.com; cheshire <redacted>; rs.ietf@gmx.at; Jason_Livingood@comcast.com; Vidhi Goel <redacted>
Subject: Re: [PATCH v10 net-next 00/15] AccECN protocol case handling series


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On Wed, Jan 21, 2026 at 3:55 PM Jakub Kicinski [off-list ref] wrote:

quoted

On Wed, 21 Jan 2026 15:32:00 +0100 chia-yu.chang@nokia-bell-labs.com
wrote:

quoted

From: Chia-Yu Chang <redacted>

Hello,

Plesae find the v10 AccECN case handling patch series, which covers
several excpetional case handling of Accurate ECN spec (RFC9768),
adds new identifiers to be used by CC modules, adds ecn_delta into
rate_sample, and keeps the ACE counter for computation, etc.

Looks like we went in the wrong directions, multiple tests are failing
now:

https://netd/
ev.bots.linux.dev%2Fcontest.html%3Fbranch%3Dnet-next-2026-01-21--18-00
%26executor%3Dvmksft-packetdrill%26pw-n%3D0%26pass%3D0&data=05%7C02%7C
chia-yu.chang%40nokia-bell-labs.com%7C1c27eff9f5224f76471508de59312151
%7C5d4717519675428d917b70f44f9630b0%7C0%7C0%7C639046264707930163%7CUnk
nown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJ
XaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=vOwUro8o0
t%2FuZYh%2BRqD6Kq4cPjYWFdAMIOicRs0ZRLE%3D&reserved=0

Looks like the first two are failing because the v10 series has a different layout for tcp_info than what packetdrill currently expects:

https://netdev-ctrl.bots.linux.dev/logs/vmksft/packetdrill/results/483641/30-tcp-accecn-delivered-updates-pkt/stdout
https://netdev-ctrl.bots.linux.dev/logs/vmksft/packetdrill/results/483641/58-tcp-accecn-delivered-falseoverflow-detect-pkt/stdout

Chia-Yu, can you please post a patch for packetdrill to make it expect the new layout from the v10 series?

For the third one:
https://netdev-ctrl.bots.linux.dev/logs/vmksft/packetdrill/results/483641/69-tcp-accecn-client-accecn-options-lost-pkt/stdout

... it looks like the test line that says:

+.002 ... 0.052 connect(4, ..., ...) = 0

needs to be changed to:

+.002 ... 0.102 connect(4, ..., ...) = 0

It seems like running the tests before emailing the patches should have caught these 3 issues?

Chia-Yu, can you please make sure you run all the AccECN packetdrill tests with the latest kernel and latest packetdrill binary you are proposing, before posting a v11 kernel patch series and packetdrill patch?

Thanks,
neal

Hi Neal,

Sorry for my miss, I only patched my local packetdrill.

So, one new patch for tcpi to packetdrill just sent out to the mailing list.

I will submit v11 kernel patch after fixing one issue raised by Eric, and doing the packetdrill run before sending them out.

Chia-Yu