RE: [PATCH v11 net-next 1/5] Documentation: netlink: specs: tc: Add DualPI2 specification

-----Original Message----- From: Paolo Abeni pabeni@redhat.com Sent: Tuesday, April 22, 2025 11:54 AM To: Chia-Yu Chang (Nokia) chia-yu.chang@nokia-bell-labs.com; xandfury@gmail.com; netdev@vger.kernel.org; dave.taht@gmail.com; jhs@mojatatu.com; kuba@kernel.org; stephen@networkplumber.org; xiyou.wangcong@gmail.com; jiri@resnulli.us; davem@davemloft.net; edumazet@google.com; horms@kernel.org; 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; ncardwell@google.com; Koen De Schepper (Nokia) koen.de_schepper@nokia-bell-labs.com; g.white g.white@cablelabs.com; ingemar.s.johansson@ericsson.com; mirja.kuehlewind@ericsson.com; cheshire@apple.com; rs.ietf@gmx.at; Jason_Livingood@comcast.com; vidhi_goel vidhi_goel@apple.com Subject: Re: [PATCH v11 net-next 1/5] Documentation: netlink: specs: tc: Add DualPI2 specification

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On 4/15/25 2:43 PM, chia-yu.chang@nokia-bell-labs.com wrote:

...

From: Chia-Yu Chang chia-yu.chang@nokia-bell-labs.com

Introduce the specification of tc qdisc DualPI2 stats and attributes, which is the reference implementation of IETF RFC9332 DualQ Coupled AQM (https://datatracker.ietf.org/doc/html/rfc9332) providing two different queues: low latency queue (L-queue) and classic queue (C-queue).

Signed-off-by: Chia-Yu Chang chia-yu.chang@nokia-bell-labs.com

Documentation/netlink/specs/tc.yaml | 144 ++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+)

diff --git a/Documentation/netlink/specs/tc.yaml b/Documentation/netlink/specs/tc.yaml index aacccea5dfe4..0fb971935285 100644 --- a/Documentation/netlink/specs/tc.yaml +++ b/Documentation/netlink/specs/tc.yaml @@ -816,6 +816,58 @@ definitions: - name: drop-overmemory type: u32

• name: tc-dualpi2-xstats
• type: struct
• members:

•  -
  

•    name: prob
  

•    type: u32
  

•    doc: Current probability
  

•  -
  

•    name: delay_c
  

•    type: u32
  

•    doc: Current C-queue delay in microseconds
  

•  -
  

•    name: delay_l
  

•    type: u32
  

•    doc: Current L-queue delay in microseconds
  

•  -
  

•    name: pkts_in_c
  

•    type: u32
  

•    doc: Number of packets enqueued in the C-queue
  

•  -
  

•    name: pkts_in_l
  

•    type: u32
  

•    doc: Number of packets enqueued in the L-queue
  

•  -
  

•    name: maxq
  

•    type: u32
  

•    doc: Maximum number of packets seen by the DualPI2
  

•  -
  

•    name: ecn_mark
  

•    type: u32
  

•    doc: All packets marked with ecn
  

•  -
  

•    name: step_mark
  

•    type: u32
  

•    doc: Only packets marked with ecn due to L-queue step AQM
  

•  -
  

•    name: credit
  

•    type: s32
  

•    doc: Current credit value for WRR
  

•  -
  

•    name: memory_used
  

•    type: u32
  

•    doc: Memory used in bytes by the DualPI2
  

•  -
  

•    name: max_memory_used
  

•    type: u32
  

Here and in other numeric fields you should probably want to use 'uint' type, that will allow either 32 or 64 bits integers depending on the actual value and will make possible overflows harder.

Hi Paolo,

OK, I will replace all u32 and u8 into uint, and s32 into int.

...

•    doc: Maximum memory used in bytes by the DualPI2
  

•  -
  

•    name: memory_limit
  

•    type: u32
  

•    doc: Memory limit in bytes
  

  • name: tc-fq-pie-xstats type: struct

@@ -2299,6 +2351,92 @@ attribute-sets: - name: quantum type: u32

• name: tc-dualpi2-attrs
• attributes:

•  -
  

•    name: limit
  

•    type: u32
  

•    doc: Limit of total number of packets in queue
  

•  -
  

•    name: memlimit
  

•    type: u32
  

•    doc: Memory limit of total number of packets in queue
  

•  -
  

•    name: target
  

•    type: u32
  

•    doc: Classic target delay in microseconds
  

•  -
  

•    name: tupdate
  

•    type: u32
  

•    doc: Drop probability update interval time in microseconds
  

•  -
  

•    name: alpha
  

•    type: u32
  

•    doc: Integral gain factor in Hz for PI controller
  

•  -
  

•    name: beta
  

•    type: u32
  

•    doc: Proportional gain factor in Hz for PI controller
  

•  -
  

•    name: step_thresh
  

•    type: u32
  

•    doc: L4S step marking threshold in microseconds or in packet (see step_packets)
  

•  -
  

•    name: step_packets
  

•    type: flags
  

•    doc: L4S Step marking threshold unit
  

•    entries:
  

•    - microseconds
  

•    - packets
  

•  -
  

•    name: min_qlen_step
  

•    type: u32
  

•    doc: Pacekts enqueued to the L-queue can apply the step 
  

• threshold when the queue length of L-queue is larger than this
• value. (0 is recommended)

Typo above, should likely be 'Packets'

/P

Thanks, this will be fixed in the next version.

BRs, Chia-Yu