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[v18,net-next,0/5] DUALPI2 patch

Message ID 20250613153725.7983-1-chia-yu.chang@nokia-bell-labs.com
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Series DUALPI2 patch | expand

Message

Chia-Yu Chang (Nokia) June 13, 2025, 3:37 p.m. UTC 
From: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>

Hello,

  Please find the DualPI2 patch v18.

  This patch serise adds DualPI Improved with a Square (DualPI2) with following features:
* Supports congestion controls that comply with the Prague requirements in RFC9331 (e.g. TCP-Prague)
* Coupled dual-queue that separates the L4S traffic in a low latency queue (L-queue), without harming remaining traffic that is scheduled in classic queue (C-queue) due to congestion-coupling using PI2 as defined in RFC9332
* Configurable overload strategies
* Use of sojourn time to reliably estimate queue delay
* Supports ECN L4S-identifier (IP.ECN==0b*1) to classify traffic into respective queues

For more details of DualPI2, please refer IETF RFC9332 (https://datatracker.ietf.org/doc/html/rfc9332).

Best regards,
Chia-Yu

---
v18 (13-Jun-2025)
- Add the num of enum used by DualPI2 and fix name and name-prefix of DualPI2 enum and attribute
- Replace from_timer() with timer_container_of() (Pedro Tammela <pctammela@mojatatu.com>)

v17 (25-May-2025, Resent at 11-Jun-2025)
- Replace 0xffffffff with U32_MAX (Paolo Abeni <pabeni@redhat.com>)
- Use helper function qdisc_dequeue_internal() and add new helper function skb_apply_step() (Paolo Abeni <pabeni@redhat.com>)
- Add s64 casting when calculating the delta of the PI controller (Paolo Abeni <pabeni@redhat.com>)
- Change the drop reason into SKB_DROP_REASON_QDISC_CONGESTED for drop_early (Paolo Abeni <pabeni@redhat.com>)
- Modify the condition to remove the original skb when enqueuing multiple GSO segments (Paolo Abeni <pabeni@redhat.com>)
- Add READ_ONCE() in dualpi2_dump_stat() (Paolo Abeni <pabeni@redhat.com>)
- Add comments, brackets, and brackets for readability (Paolo Abeni <pabeni@redhat.com>)

v16 (16-MAy-2025)
- Add qdisc_lock() to dualpi2_timer() in dualpi2_timer (Paolo Abeni <pabeni@redhat.com>)
- Introduce convert_ns_to_usec() to convert usec to nsec without overflow in #1 (Paolo Abeni <pabeni@redhat.com>)
- Update convert_us_tonsec() to convert nsec to usec without overflow in #2 (Paolo Abeni <pabeni@redhat.com>)
- Add more descriptions with respect to DualPI2 in the cover ltter and add changelog in each patch (Paolo Abeni <pabeni@redhat.com>)

v15 (09-May-2025)
- Add enum of TCA_DUALPI2_ECN_MASK_CLA_ECT to remove potential leakeage in #1 (Simon Horman <horms@kernel.org>)
- Fix one typo in comment of #2
- Update tc.yaml in #5 to aligh with the updated enum of pkt_sched.h

v14 (05-May-2025)
- Modify tc.yaml: (1) Replace flags with enum and remove enum-as-flags, (2) Remove credit-queue in xstats, and (3) Change attribute types (Donald Hunter <donald.hun
- Add enum and fix the ordering of variables in pkt_sched.h to align with the modified tc.yaml (Donald Hunter <donald.hunter@gmail.com>)
- Add validators for DROP_OVERLOAD, DROP_EARLY, ECN_MASK, and SPLIT_GSO in sch_dualpi2.c (Donald Hunter <donald.hunter@gmail.com>)
- Update dualpi2.json to align with the updated variable order in pkt_sched.h
- Reorder patches (Donald Hunter <donald.hunter@gmail.com>)

v13 (26-Apr-2025)
- Use dashes in member names to follow YNL conventions in tc.yaml (Donald Hunter <donald.hunter@gmail.com>)
- Define enumerations separately for flags of drop-early, drop-overload, ecn-mask, credit-queue in tc.yaml (Donald Hunter <donald.hunter@gmail.com>)
- Change the types of split-gso and step-packets into flag in tc.yaml (Donald Hunter <donald.hunter@gmail.com>)
- Revert to u32/u8 types for tc-dualpi2-xstats members in tc.yaml (Donald Hunter <donald.hunter@gmail.com>)
- Add new test cases in tc-tests/qdiscs/dualpi2.json to cover all dualpi2 parameters (Donald Hunter <donald.hunter@gmail.com>)
- Change the type of TCA_DUALPI2_STEP_PACKETS into NLA_FLAG (Donald Hunter <donald.hunter@gmail.com>)


v12 (22-Apr-2025)
- Remove anonymous struct in sch_dualpi2.c (Paolo Abeni <pabeni@redhat.com>)
- Replace u32/u8 with uint and s32 with int in tc spec document (Paolo Abeni <pabeni@redhat.com>)
- Introduce get_memory_limit function to handle potential overflow when multipling limit with MTU (Paolo Abeni <pabeni@redhat.com>)
- Double the packet length to further include packet overhead in memory_limit (Paolo Abeni <pabeni@redhat.com>)
- Remove the check of qdisc_qlen(sch) when calling qdisc_tree_reduce_backlog (Paolo Abeni <pabeni@redhat.com>)

v11 (15-Apr-2025)
- Replace hstimer_init with hstimer_setup in sch_dualpi2.c

v10 (25-Mar-2025)
- Remove leftover include in include/linux/netdevice.h and anonymous struct in sch_dualpi2.c (Paolo Abeni <pabeni@redhat.com>)
- Use kfree_skb_reason() and add SKB_DROP_REASON_DUALPI2_STEP_DROP drop reason (Paolo Abeni <pabeni@redhat.com>)
- Split sch_dualpi2.c into 3 patches (and overall 5 patches): Struct definition & parsing, Dump stats & configuration, Enqueue/Dequeue (Paolo Abeni <pabeni@redhat.com>)

v9 (16-Mar-2025)
- Fix mem_usage error in previous version
- Add min_qlen_step to the dualpi2 attribute as the minimum queue length in number of packets in the L-queue to start step threshold marking.
  In previous versions, this value was fixed to 2, so the step threshold was applied to mark packets in the L queue only when the queue length of the L queue was greater than or equal to 2 packets.
  This will cause larger queuing delays for L4S traffic at low rates (<20Mbps). So we parameterize it and change the default value to 0.
  Comparison of tcp_1down run 'HTB 20Mbit + DUALPI2 + 10ms base delay'
    Old versions:
                           avg       median          # data pts
 Ping (ms) ICMP :        11.55        11.70 ms              350
 TCP upload avg :        18.96          N/A Mbits/s         350
 TCP upload sum :        18.96          N/A Mbits/s         350

    New version (v9):
                           avg       median          # data pts
 Ping (ms) ICMP :        10.81        10.70 ms              350
 TCP upload avg :        18.91          N/A Mbits/s         350
 TCP upload sum :        18.91          N/A Mbits/s         350


  Comparison of tcp_1down run 'HTB 10Mbit + DUALPI2 + 10ms base delay'
    Old versions:
                           avg       median          # data pts
 Ping (ms) ICMP :        12.61        12.80 ms              350
 TCP upload avg :         9.48          N/A Mbits/s         350
 TCP upload sum :         9.48          N/A Mbits/s         350

    New version (v9):
                           avg       median          # data pts
 Ping (ms) ICMP :        11.06        10.80 ms              350
 TCP upload avg :         9.43          N/A Mbits/s         350
 TCP upload sum :         9.43          N/A Mbits/s         350


  Comparison of tcp_1down run 'HTB 10Mbit + DUALPI2 + 10ms base delay'
    Old versions:
                           avg       median          # data pts
 Ping (ms) ICMP :        40.86        37.45 ms              350
 TCP upload avg :         0.88          N/A Mbits/s         350
 TCP upload sum :         0.88          N/A Mbits/s         350
 TCP upload::1  :         0.88         0.97 Mbits/s         350

    New version (v9):
                           avg       median          # data pts
 Ping (ms) ICMP :        11.07        10.40 ms              350
 TCP upload avg :         0.55          N/A Mbits/s         350
 TCP upload sum :         0.55          N/A Mbits/s         350
 TCP upload::1  :         0.55         0.59 Mbits/s         350

v8 (11-Mar-2025)
- Fix warning messages in v7

v7 (07-Mar-2025)
- Separate into 3 patches to avoid mixing changes of documentation, selftest, and code. (Cong Wang <xiyou.wangcong@gmail.com>)

v6 (04-Mar-2025)
- Add modprobe for dulapi2 in tc-testing script tc-testing/tdc.sh (Jakub Kicinski <kuba@kernel.org>)
- Update test cases in dualpi2.json
- Update commit message

v5 (22-Feb-2025)
- A comparison was done between MQ + DUALPI2, MQ + FQ_PIE, MQ + FQ_CODEL:
  Unshaped 1gigE with 4 download streams test:
   - Summary of tcp_4down run 'MQ + FQ_CODEL':
                             avg       median       # data pts
      Ping (ms) ICMP :       1.19     1.34 ms          349
      TCP download avg :   235.42      N/A Mbits/s     349
      TCP download sum :   941.68      N/A Mbits/s     349
      TCP download::1  :   235.19   235.39 Mbits/s     349
      TCP download::2  :   235.03   235.35 Mbits/s     349
      TCP download::3  :   236.89   235.44 Mbits/s     349
      TCP download::4  :   234.57   235.19 Mbits/s     349

   - Summary of tcp_4down run 'MQ + FQ_PIE'
                             avg       median        # data pts
      Ping (ms) ICMP :       1.21     1.37 ms          350
      TCP download avg :   235.42      N/A Mbits/s     350
      TCP download sum :   941.61     N/A Mbits/s      350
      TCP download::1  :   232.54  233.13 Mbits/s      350
      TCP download::2  :   232.52  232.80 Mbits/s      350
      TCP download::3  :   233.14  233.78 Mbits/s      350
      TCP download::4  :   243.41  241.48 Mbits/s      350

   - Summary of tcp_4down run 'MQ + DUALPI2'
                             avg       median        # data pts
      Ping (ms) ICMP :       1.19     1.34 ms          349
      TCP download avg :   235.42      N/A Mbits/s     349
      TCP download sum :   941.68      N/A Mbits/s     349
      TCP download::1  :   235.19   235.39 Mbits/s     349
      TCP download::2  :   235.03   235.35 Mbits/s     349
      TCP download::3  :   236.89   235.44 Mbits/s     349
      TCP download::4  :   234.57   235.19 Mbits/s     349


  Unshaped 1gigE with 128 download streams test:
   - Summary of tcp_128down run 'MQ + FQ_CODEL':
                             avg       median       # data pts
      Ping (ms) ICMP   :     1.88     1.86 ms          350
      TCP download avg :     7.39      N/A Mbits/s     350
      TCP download sum :   946.47      N/A Mbits/s     350

   - Summary of tcp_128down run 'MQ + FQ_PIE':
                             avg       median       # data pts
      Ping (ms) ICMP   :     1.88     1.86 ms          350
      TCP download avg :     7.39      N/A Mbits/s     350
      TCP download sum :   946.47      N/A Mbits/s     350

   - Summary of tcp_128down run 'MQ + DUALPI2':
                             avg       median       # data pts
      Ping (ms) ICMP   :     1.88     1.86 ms          350
      TCP download avg :     7.39      N/A Mbits/s     350
      TCP download sum :   946.47      N/A Mbits/s     350


  Unshaped 10gigE with 4 download streams test:
   - Summary of tcp_4down run 'MQ + FQ_CODEL':
                             avg       median       # data pts
      Ping (ms) ICMP :       0.22     0.23 ms          350
      TCP download avg :  2354.08      N/A Mbits/s     350
      TCP download sum :  9416.31      N/A Mbits/s     350
      TCP download::1  :  2353.65  2352.81 Mbits/s     350
      TCP download::2  :  2354.54  2354.21 Mbits/s     350
      TCP download::3  :  2353.56  2353.78 Mbits/s     350
      TCP download::4  :  2354.56  2354.45 Mbits/s     350

  - Summary of tcp_4down run 'MQ + FQ_PIE':
                             avg       median      # data pts
      Ping (ms) ICMP :       0.20     0.19 ms          350
      TCP download avg :  2354.76      N/A Mbits/s     350
      TCP download sum :  9419.04      N/A Mbits/s     350
      TCP download::1  :  2354.77  2353.89 Mbits/s     350
      TCP download::2  :  2353.41  2354.29 Mbits/s     350
      TCP download::3  :  2356.18  2354.19 Mbits/s     350
      TCP download::4  :  2354.68  2353.15 Mbits/s     350

   - Summary of tcp_4down run 'MQ + DUALPI2':
                             avg       median      # data pts
      Ping (ms) ICMP :       0.24     0.24 ms          350
      TCP download avg :  2354.11      N/A Mbits/s     350
      TCP download sum :  9416.43      N/A Mbits/s     350
      TCP download::1  :  2354.75  2353.93 Mbits/s     350
      TCP download::2  :  2353.15  2353.75 Mbits/s     350
      TCP download::3  :  2353.49  2353.72 Mbits/s     350
      TCP download::4  :  2355.04  2353.73 Mbits/s     350


  Unshaped 10gigE with 128 download streams test:
   - Summary of tcp_128down run 'MQ + FQ_CODEL':
                             avg       median       # data pts
      Ping (ms) ICMP   :     7.57     8.69 ms          350
      TCP download avg :    73.97      N/A Mbits/s     350
      TCP download sum :  9467.82      N/A Mbits/s     350

   - Summary of tcp_128down run 'MQ + FQ_PIE':
                             avg       median       # data pts
      Ping (ms) ICMP   :     7.82     8.91 ms          350
      TCP download avg :    73.97      N/A Mbits/s     350
      TCP download sum :  9468.42      N/A Mbits/s     350

   - Summary of tcp_128down run 'MQ + DUALPI2':
                             avg       median       # data pts
      Ping (ms) ICMP   :     6.87     7.93 ms          350
      TCP download avg :    73.95      N/A Mbits/s     350
      TCP download sum :  9465.87      N/A Mbits/s     350

   From the results shown above, we see small differences between combinations.
- Update commit message to include results of no_split_gso and split_gso (Dave Taht <dave.taht@gmail.com> and Paolo Abeni <pabeni@redhat.com>)
- Add memlimit in the dualpi2 attribute, and add memory_used, max_memory_used, memory_limit in dualpi2 stats (Dave Taht <dave.taht@gmail.com>)
- Update note in sch_dualpi2.c related to BBRv3 status (Dave Taht <dave.taht@gmail.com>)
- Update license identifier (Dave Taht <dave.taht@gmail.com>)
- Add selftest in tools/testing/selftests/tc-testing (Cong Wang <xiyou.wangcong@gmail.com>)
- Use netlink policies for parameter checks (Jamal Hadi Salim <jhs@mojatatu.com>)
- Modify texts & fix typos in Documentation/netlink/specs/tc.yaml (Dave Taht <dave.taht@gmail.com>)
- Add descriptions of packet counter statistics and the reset function of sch_dualpi2.c
- Fix step_thresh in packets
- Update code comments in sch_dualpi2.c

v4 (22-Oct-2024)
- Update statement in Kconfig for DualPI2 (Stephen Hemminger <stephen@networkplumber.org>)
- Put a blank line after #define in sch_dualpi2.c (Stephen Hemminger <stephen@networkplumber.org>)
- Fix line length warning.

v3 (19-Oct-2024)
- Fix compilaiton error
- Update Documentation/netlink/specs/tc.yaml (Jakub Kicinski <kuba@kernel.org>)

v2 (18-Oct-2024)
- Add Documentation/netlink/specs/tc.yaml (Jakub Kicinski <kuba@kernel.org>)
- Use dualpi2 instead of skb prefix (Jamal Hadi Salim <jhs@mojatatu.com>)
- Replace nla_parse_nested_deprecated with nla_parse_nested (Jamal Hadi Salim <jhs@mojatatu.com>)
- Fix line length warning

---
Chia-Yu Chang (4):
  sched: Struct definition and parsing of dualpi2 qdisc
  sched: Dump configuration and statistics of dualpi2 qdisc
  selftests/tc-testing: Add selftests for qdisc DualPI2
  Documentation: netlink: specs: tc: Add DualPI2 specification

Koen De Schepper (1):
  sched: Add enqueue/dequeue of dualpi2 qdisc

 Documentation/netlink/specs/tc.yaml           |  161 +++
 include/net/dropreason-core.h                 |    6 +
 include/uapi/linux/pkt_sched.h                |   70 +-
 net/sched/Kconfig                             |   12 +
 net/sched/Makefile                            |    1 +
 net/sched/sch_dualpi2.c                       | 1146 +++++++++++++++++
 tools/testing/selftests/tc-testing/config     |    1 +
 .../tc-testing/tc-tests/qdiscs/dualpi2.json   |  254 ++++
 tools/testing/selftests/tc-testing/tdc.sh     |    1 +
 9 files changed, 1651 insertions(+), 1 deletion(-)
 create mode 100644 net/sched/sch_dualpi2.c
 create mode 100644 tools/testing/selftests/tc-testing/tc-tests/qdiscs/dualpi2.json