PSA Meeting Minutes Nov 1, 2017

Attendees:

• AndyF, Tom, Han, Vlad, Calin
• online: AndyK, Samar, James Coole

Agenda

• AIs from last time (10 min):
  • Action profiles (Samar) - https://github.com/p4lang/p4-spec/pull/449
  • Digest (Han) - https://github.com/p4lang/p4-spec/pull/419 -- need example(s)
  • IntenetChecksum get_state, set_state (Andy)
  • PRE, BQE moved to top (Han)
• Clone, resubmit, recirculate (Han) - 45 min
  • Semantics: https://github.com/p4lang/p4-spec/pull/423
  • More examples - https://github.com/p4lang/p4-spec/pull/448, https://github.com/p4lang/p4-spec/pull/428
  • Bridged metadata (Andy)
• Default metadata values for all packet types (Andy) (20 min)
  • please review spreadsheet before the meeting: https://github.com/p4lang/p4-spec/files/1395146/psa-packet-paths.zip
• Open issues

Discussion

Action profiles

• added the max group size
• flexibility in programming the members
  • two different PSA targets that program groups in both targets and use the same P4 program
    • how do we handle the case when the targets have different sizes ( https://github.com/p4lang/p4-spec/issues/456)
    • Proposal: have an additional constructor w/o max_size
    • Vlad: can the controller use a query API and make the decision outside PSA?
    • Andy: can we provide more bits than the platform supports but accepts and ignores the extra?
    • Do we need multiple sizes (min-max)?
  • Liveness of action profile members (https://github.com/p4lang/p4-spec/issues/457)
    • separate port management/notification from action profiles
• AI: group to review the issues and discuss on github.

Digest

• https://github.com/p4lang/p4-spec/pull/454
• change the digests from having an id to an instantiation. The instance then can be used as a name to help generate control plane API.
• AI Han
  • add constructor parameter with a struct that captures the data serialized
  • add example that shows more than one instantiation

InternetChecksum

• get_state -> save to metadata -> ... -> set_state + add
• options: change update, remove to add, subtract
• add set_state & get_state as new operations
• keep clear and init
• keep get for getting the complemented value
• discussion
  • what should we do about negation?
    • set could do the complement
    • get_checksum -- the one that complements
  • decision: too complicated
• agreed that we instantiate the extern in a cleared state
• AI Andy to create a PR capturing these changes.

PRE & BQE

• remove from control blocks and keep in package
• approved!

Cloning/resubmit/recirculate/bridging

• discussed the pack proposal
• discussed https://github.com/p4lang/p4-spec/pull/448
  • need some way to capture the user defined metadata, outside the architecture defined intrinsic metadata
  • define a union of each packet path
  • AI (Andy): add the option with parameters

Default metadata values

• did not have time to discuss in detail
• agreed to merge PR and get community feedback

Draft release for Nov 10

• Andy and Calin to merge all outstanding PRs before the weekend
• Weekend and next week will be spend in editorial mode
• Calin to add a Known Issue section