Zephyr: TSC Meeting Minutes (7/8/20 - Virtual TSC F2F)

Brett Preston

Zephyr Project TSC - 8 July 2020


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[In blue meeting notes, in purple post meeting addendums]

Voting TSC Members in Attendance [12 = quorum] - Quorum reached

Voting TSC Member


Voting TSC Member


Voting TSC Member


Amber Hibberd


Ioannis Glaropoulos


Nate Graff


Anas Nashif


Johan Hedberg


Piotr Mienkowski


Asger Munk Nielsen 


Johann Fischer


Rasmus Abildgren


Carles Cufi


Kumar Gala (Kevin Townsend - alternate)


Ruud Derwig


Danny Ørndrup


Mark Grosen


Ryan Erickson


David Brown


Maureen Helm


Scott Shawcroft


David Eriksson (Joel Westerberg - alternate)


Michael Gielda (Peter Gielda - alternate)


Stefan Mijovic


David Leach


Michael Scott


Out of Office / Vacations

  • TSC Member Name - Dates

    • Stefan Mijovic - until July 29


  • GitHub Permissions - Next Steps:

    • Map GitHub terms (code owner, member, collaborator, owner) to Zephyr Project charter terms (maintainer, committer, contributor)

    • Define process to grant and revoke merge rights and code ownership

  • Safety Committee [Amber]


  • Strategic Objectives [Maureen]

    • Technical Steering Committee:

      • The Zephyr Project will:

  • Support development on Linux, Windows, and MacOS host operating systems.

    • Discussion:

    • [Kevin T] Breakdown on Linux vs. Windows vs. MacOS users?

    • [Anas] A lot of demand for Windows.

    • Consensus that goal should remain for support across all 3

    • [Anas] Bigger topic - How much do we want to invest in the SDK / How far do we want to take it?

    • [Asger] On Linux, as a developer, it’s much more of a fluid experience. Maybe we need to accept that there are 2 modes of operation.

    •  [Anas] It may be time for another Developer/User Survey

    • [Maureen] Kate is planning a survey right now

    • AI - All: If you have questions to place on the survey (targeting end of month), please send to Maureen/Kate

      • Copy requested for TSC review

      • Need to ensure it’s technical enough to prove helpful for future roadmap

      • Suggested questions to include/add:

        • What operating system are you running

    • [David B] Any other Projects with similar scope that we could look at surveys they have done?

    • [Henrik] Consider looking at new Linux system on Windows 10

      • [Maureen] Stops at USB

      • [Carles] Still have several Product development companies on Windows 7

    • [Kumar] Probably need to spend a little time on deciding on what are the official platforms that are tested, documented

    • [Maureen] What to do in cases/issues when folks file issues/bugs on platforms not included under the official list of supported platforms

      • Close, pointing folks to official list/Slack

  • Support development with GCC and commercial toolchains.

  • Maintain long term support (LTS) releases for at least two years.

  • Make the second long term support (LTS2) release two years after the first (LTS1).

  • Make mainline releases quarterly until May 2020, then every 4 months afterward.

    • Discussion:

    • Update wording (May is already past)

  • Use continuous integration builds and automated checks to validate pull requests, release branches, and the mainline branch.

  • Test release candidates on hardware and consolidate results in TestRail.

    • Discussion:

    • Decided to go away from TestRail

  • Review and update APIs to be suitable for Zephyr applications and compatible with hardware from multiple vendors.

  • Qualify the Bluetooth stack with the latest version of the Bluetooth standard.

    • Discussion:

    • Specify host or host + controller

    • Proposed: Update to host and mesh

    • [Johan] Should still strive to have the controller supporting the latest version

    • [Carles] Replace “stack” with “host and mesh.”

  • Support small memory footprints under ??? KB

    • Discussion:

    • [David L] Did we have a target number that we wanted to have?

    • [Anas] In terms of doing something useful, 16k is the limit

    • [Anas] Features will always come with footprint if they are justified

    • [Maureen] Challenge that keeps coming up is around the balance between memory footprint and other priorities; acknowledge members who care about small memory footprint

    • [David L] Being more aware of how things grow or shrink over time

    • [Anas] Propose updating the Strategic Objective to something like: Project is conscious about footprint requirements for constrained devices (and tracking over time). Not specifying a number.

    • [Anas] Should set some policies about you shouldn’t build something if you don’t need it

    • [Anas] Look at ninja puncover as example

    • AI - Need to revisit tracking footprint and providing additional data

    • [Kumar] Request for close of virtual meeting -- Try to put some priority on actions identified in the meeting(s)

    • [Carles] Once we have a prioritized list, suggest status checks as part of TSC meetings (versus solely in the F2F meetings)

  • Publish documentation and sample applications that demonstrate how to use the kernel, drivers, and subsystems.

  • Engage community developers at all levels, including occasional hobbyists, nonmembers, and member company employees.

    • [Anas] Enhance the last bullet to include more community surveys

    • [Scott] At Adafruit, our only audience is hobbyists

    • [Kumar] Presentation last week from CHAOSS. Need to think about what questions/metrics we need to track.

    • [Kevin] Would love to see more work around sensors

    • [Carles] One thing that would help a lot is having some examples of more advanced Projects -- out of tree project example

    • [Kevin] Try to get some samples around easier to source boards

  • AI - Maureen: Add low power to the list, in addition to footprint and performance

  • Roadmap Planning to LTS2 [Maureen]

    • Release Plan: https://github.com/zephyrproject-rtos/zephyr/projects/9

    • [Anas] API freeze part makes sense (need 2 Releases for an API to freeze)

    • [Kumar] Working backwards, is it all going to land in 2.4? Understand the desire.

      • [Anas] All depends on how much we can get into 2.4

      • [Kumar] What are the key things for LTS -- sets the priority

    • Think through: What does the 2.x LTS get you, that the 1.x LTS doesn’t?

    • Power management, DTS

    • [Carles] Prioritization of things we want to do for the Project in general; LTS prioritization (2.6)

    • [Kumar] Value in distinguishing roadmap into user categories?

    • Other big items: Need to have more and need to prioritize them

    • [Anas] For LTS, delta between now and LTS -- a lot of things since last year that would be part of the LTS 2. Don’t foresee having a problem around having a full list differentiating between LTS 1 and LTS 2.

      • [Kumar] Driver API stabilization

      • [Anas] Audio support - SOF (Sound-open-firmware)

      • [Carles] 32-bit Cortex-A support, Paging support

      • [Kumar] Start Release Notes LTS 2? Clean up as part of 2.6 Release (holding spot to start tracking) // Add as cards under 2.6

      • [Kumar] Toolchain (IAR) - what will we realistically be able to say for 2.6? Aiming for full IAR compile link support? User visible statement

        • That’s the plan

      • [Anas] 2.6 Release criteria tracking

      • [Carles] Would like to have I2S and I2C for LTS 2

      • AI - All: Request folks working on 2.6/LTS2 to start adding Cards, Github issues

  • PR Backlog [Kumar]

    • We seem to keep growing the backlog - at 550 Open

    • What type of metrics should we try to track? Use Labels as a way to categorize what areas we are lagging in?

    • Some of this is due to the change of going to 2 reviewers

    • How do we grow the review pool? Identify people we should be asking for reviews from

    • Feels like the Project has more engagement - good thing! - How do we convert some of them to reviewers/maintainers/etc ; work on backlog

    • [Carles] What is the action that could be most effective?

    • [Kumar] If there’s new people, try to figure out areas they may be focusing on?

      • What areas are getting underserved?

      • How to identify who may be contributing to areas who could help?

    • [Anas] First thing I would do is a general clean-up; have been very relaxed with how people are contributing PRs (a lot of draft PRs); a lot of DNM; some sitting there for 1 year+

      • Draft: 66 Open

      • DNM: 62 Open

      • Has Conflicts: x

      • Removing the above, you reduce number to 321 Open PRs

      • Also to note -- No Reviews: 121

    • [Anas] Main problem is the noise. Another problem is that we need to have people review more than they are comfortable.

    • Maintainers file needs to be finalized and pushed

      • Once it’s there, people will start updating/approving

    • [Maureen] Maybe we just have Release Team start assigning manually until it’s automated

      • [Anas] Need to finalize the maintainers file before we can start automating

    • [Kumar] PRs without assignee -- review in the Release Meeting

    • [Kumar] May need to update policy on Draft PRs and DNMs and how long they are allowed to stay open?

    • [Anas] In the past (Gerrit), we were sending emails with the new things from the last day; things that are lagging

    • [Ioannis] How can we make sure the Release Team doesn’t merge something not ready to merge?

      • [Kumar] There are a few labels that should only apply to Draft PRs

      • [Anas] Scan the PR for certain labels and disable merging if they are present

      • [from chat] Can look at https://github.com/Muhnad/dont-merge

      • [Maureen] Encourage using Draft status more?

      • [Anas] Suggest any changes to West, automatically switch to DNM

      • [Kumar] Does it have the assignees approval? It may have others, but has the assignee signed off?

      • [Maureen] If the assignee has +1’d, then it’s mergeable (caveat: if assignee is also the author)


CFP Open (closes July 26): https://events.linuxfoundation.org/open-source-summit-europe/program/cfp/

*** Previous minutes available at: https://docs.google.com/document/d/1xiO721JwqW_H_BpGMOJ4PY3vLVy7nxW2fhy841nsP10/edit#heading=h.x36xe8bnwr9r

Brett Preston
The Linux Foundation
+1 (971) 303-9030

Google Talk: bpreston@...
Skype: bprestoncf

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