Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

P0443 A Unified Executors Proposal for C++ #102

Open
jensmaurer opened this issue Jan 26, 2019 · 15 comments
Open

P0443 A Unified Executors Proposal for C++ #102

jensmaurer opened this issue Jan 26, 2019 · 15 comments

Comments

@jensmaurer
Copy link
Member

@jensmaurer jensmaurer commented Jan 26, 2019

P0443R9 A Unified Executors Proposal for C++ (Jared Hoberock, Michael Garland, Chris Kohlhoff, Chris Mysen, H. Carter Edwards, Gordon Brown)

@jensmaurer jensmaurer added this to the 2019-02 milestone Jan 26, 2019
@jensmaurer
Copy link
Member Author

@jensmaurer jensmaurer commented Jan 31, 2019

Discussed in joint LEWG / SG1 session in San Diego: http://wiki.edg.com/bin/view/Wg21sandiego2018/P0443R9 .

The SG1 design of P0443 is ready for inclusion in C++20, we forward P0443 to LEWG for design review (Wording for LWG pending).

SF F N A SA
8 16 1 7 0
@jensmaurer
Copy link
Member Author

@jensmaurer jensmaurer commented Jan 31, 2019

P0443R10 A Unified Executors Proposal for C++ (Jared Hoberock, Michael Garland, Chris Kohlhoff, Chris Mysen, H. Carter Edwards, Gordon Brown, Daisy Hollman)

@jensmaurer jensmaurer removed the SG1 label Jan 31, 2019
@jensmaurer jensmaurer added this to Tuesday in LEWG in Kona 2019 Feb 6, 2019
@ogiroux ogiroux added the SG1 label Feb 14, 2019
@ogiroux ogiroux added this to Friday in SG1KonaFeb2019 Feb 14, 2019
@ogiroux ogiroux moved this from Friday to Wednesday in SG1KonaFeb2019 Feb 17, 2019
@jensmaurer jensmaurer modified the milestones: 2019-02, 2019-07 Feb 26, 2019
@ogiroux
Copy link
Collaborator

@ogiroux ogiroux commented Mar 29, 2019

SG1 poll:
"If P0443 is adopted in the IS, the papers P1322R0 and P0958R1 should be
applied to the draft of the Networking TS prior to adopting the TS wording
into the IS or future TS ."
Unanimous consent.

@ogiroux ogiroux added this to Tuesday in SG1 in Cologne 2019 Jul 13, 2019
@ogiroux ogiroux moved this from Tuesday to Not Discussed in SG1 in Cologne 2019 Jul 15, 2019
@jensmaurer jensmaurer modified the milestones: 2019-07, 2019-11 Aug 23, 2019
@wg21bot
Copy link
Collaborator

@wg21bot wg21bot commented Oct 15, 2019

P0443R11 A Unified Executors Proposal for C++ (Jared Hoberock, Michael Garland, Chris Kohlhoff, Chris Mysen, Carter Edwards, Gordon Brown, Daisy Hollman, Lee Howes, Kirk Shoop, Eric Niebler)

@FabioFracassi FabioFracassi added this to C++23 Priority in LEWGBelfast2019 Oct 24, 2019
@FabioFracassi FabioFracassi moved this from C++23 Priority to Thursday Morning (Executors & generalised callbacks) in LEWGBelfast2019 Oct 30, 2019
@ogiroux ogiroux added this to Tuesday in SG1Belfast2019 Nov 3, 2019
@ogiroux
Copy link
Collaborator

@ogiroux ogiroux commented Nov 8, 2019

We adopt the design of P0443R11 for ship vehicle TBD (i.e. new papers should
be written assuming it is the basline they build upon or modify):
SF F N A SA
17 17 1 0 0
Unanimous consent

We recommend the design of P0443R11 for C++23.
SF F N A SA
14 8 6 5 1
SA: still too new and are missing experience with a lot of use-cases
Consensus

@ogiroux
Copy link
Collaborator

@ogiroux ogiroux commented Nov 8, 2019

@wg21bot
Copy link
Collaborator

@wg21bot wg21bot commented Jan 18, 2020

P0443R12 A Unified Executors Proposal for C++ (Jared Hoberock, Michael Garland, Chris Kohlhoff, Chris Mysen, Carter Edwards, Gordon Brown, Daisy Hollman, Lee Howes, Kirk Shoop, Lewis Baker, Eric Niebler)

@wg21bot wg21bot modified the milestones: 2019-11, 2020-02 Jan 18, 2020
@ogiroux ogiroux added this to Monday in SG1 Prague Feb 6, 2020
@ogiroux ogiroux moved this from Monday to Tuesday in SG1 Prague Feb 9, 2020
@tituswinters
Copy link
Collaborator

@tituswinters tituswinters commented Feb 13, 2020

Discussed in Prague

We approve of the design and want to review details and wording in Varna.
SF F N A SA
22 12 6 0 0

@ogiroux
Copy link
Collaborator

@ogiroux ogiroux commented Feb 14, 2020

SG1 in Prague.

Expecting wording ready for review in Varna.

@jensmaurer jensmaurer removed this from the 2020-02 milestone Feb 18, 2020
@wg21bot wg21bot added this to the 2020-telecon milestone Mar 24, 2020
@brycelelbach brycelelbach added this to 2020-04-20 Telecon in Library Evolution Telecons Apr 18, 2020
@jensmaurer
Copy link
Member Author

@jensmaurer jensmaurer commented Apr 24, 2020

P0443R13 A Unified Executors Proposal for C++ (Jared Hoberock, Michael Garland, Chris Kohlhoff, Chris Mysen, Carter Edwards, Gordon Brown, Daisy Hollman, Lee Howes, Kirk Shoop, Lewis Baker, Eric Niebler)

@wg21bot
Copy link
Collaborator

@wg21bot wg21bot commented Sep 23, 2020

P0443R14 A Unified Executors Proposal for C++ (Jared Hoberock, Michael Garland, Chris Kohlhoff, Chris Mysen, H. Carter Edwards, Gordon Brown, David Hollman)

@cplusplus cplusplus deleted a comment from billy-baker Oct 20, 2020
@cplusplus cplusplus deleted a comment from FabioFracassi Oct 20, 2020
@brycelelbach
Copy link
Collaborator

@brycelelbach brycelelbach commented Oct 20, 2020

2020 Summary Library Evolution Review

2020-06-29 and 2020-07-07 Library Evolution Review

2020-06-29 and 2020-07-07 Library Evolution Minutes - D2202R0 Executors Review Report: Sender/Receiver Concepts

Chair: Nevin Liber and Fabio Fracassi

Champion: Gašper Ažman

Minute Taker: Ben Craig

2020-07-07 Library Evolution Minutes - D2203R0 Executors Review Report: Customization Points

Chair: Fabio Fracassi

Champion: Ryan McDougall

Minute Taker: Ben Craig

Summary

We reviewed D2022R0 Sender/Receiver Review Report and D2203R0 Customization Point Report
The Sender/Reciever report will be compiled into concrete questions to be polled at a later date.

POLL: We want to make the selection of Executor <-> Scheduler interoperation adapters more explicit and not provide implicit defaults (esp. setting terminate as the error channel when calling the execute cpo). Given the history of the consensus of R0443 this would need a paper.

Strongly For Weakly For Neutral Weakly Against Strongly Against
2 16 5 2 1

SA: The poll was taken without the primary dissenter

Attendance: 27

# of Authors: 8

Outcome

This and the previous session were mostly informational, to identify open questions and make sure that we properly understand the programming model that we are integrating with Executors and Sender/Receivers.

One outcome is that we need lots of additional documentation and examples to make informed decisions, since the programming model (and the domain) is complex. Also to evaluate the proposed concepts we need to understand the algorithms in P1897 or P1898.

Most open issues we discovered seem to be at the seams and interactions between the two models Sender/Receiver and Executors, especially in the way that errors and cancelations are propagated between the two models.

2020-07-21 Library Evolution Review

2020-07-21 Library Evolution Minutes - P2207R0 Executors Review Report: Executor Concept

Chair: Nevin Liber

Champion: Guy Davidson

Minute Taker: Ben Craig

Outcome

The executors proposal needs to collect the history behind the decisions and put it in one place. It is impossible to do a design review w/o the knowledge of how we got here.

Executor type traits: do we want traits bundled into a few large-ish classes that users specialize, or do we want many small-ish classes instead? As this applies to more than just executors, authors and participants want guidance from LEWG. No one has yet volunteered to write such a paper.

Shape concept: We shouldn't have it yet, as it isn't generic (size_t), we don't have algorithms that use it.

Swapping executors (exceptions, thread safety, etc.): it turns out they currently are not required to be assignable, so not swappable, but that may just be an oversight. Authors will revisit this.

Namespace execution being too long: no suggestions; authors can (as always) come up with other alternatives and present them if they should so choose.

2020-07-27 and 2020-08-04 Library Evolution Review

2020-07-27 and 2020-08-04 Library Evolution Minutes - P2183R0 Executors Review Report: Properties

Chair: Ben Craig and Billy Baker

Champion: David Olsen

Minute Taker: Inbal Levi

Summary

The following poll was taken regarding RTTI overhead from any_executor<P...>::target_type (section 5.6 of P2183 Executor Review: Properties).

POLL: We should remove any_executor<P...>::target_typ.

Strongly Favor Weakly Favor Neutral Weakly Against Strongly Against
3 4 7 0 0

Attendance: 28

# of Authors: 2

Author Position: neutral

Outcome

We had consensus for removing target_type from any_executor to eliminate RTTI-related overhead. This removal is consistent with recent decisions to not include target/target_type in any_invocable (see the discussion of P0288 any_invocable from San Diego 2018). P1322 Networking TS enhancement presents a case for using target_type. The authors of P0433R13 are encouraged to explore the properties approach shown in P2183 as well as other alternatives such as the unchecked any_cast possibility raised during the presentation of P2183.

2020-08-18 Library Evolution Review

2020-08-18 Library Evolution Minutes - P2205R0 Executors Review Report: Polymorphic Executor

Chair: Fabio Fracassi

Champion: Inbal Levi

Minute Taker: Ben Craig

2020-08-24 Library Evolution Review

2020-08-24 Library Evolution Minutes - P2206R0 Executors Review Report: Thread Pool

Chair: Nevin Liber

Champion: Ruslan Arutyunyan

Minute Taker: Ben Craig

@brycelelbach
Copy link
Collaborator

@brycelelbach brycelelbach commented Oct 23, 2020

2020 Fall Final Pre Poll Discussion

2020-10-22 Library Evolution Telecon Minutes - Final Pre 2020 Fall Polls Discussion

Chair: Bryce Adelstein Lelbach

Minute Taker: Ben Craig

Start Ruslan's Presentation: 2020-10-22 13:03 Pacific

End Ruslan's Presentation, Start Review of Executors Polls: 13:19

These polls will not be reworded unless there are grave errors; the poll wording has been circulating for two weeks, and we don't want to make last minute changes.

"Remove" polls (2 and 3): These things require effort to review and to specify, and aren't necessarily fundamental. I want to determine how strongly we feel about keeping them in the core proposal.

End Review of Executors Polls: 13:55

SUMMARY: A brief presentation was given by on the relationship of schedulers and executors in P0443 by Ruslan Arutyunyan. A discussion of possible ways of unifying schedulers and executors followed. Ultimately, this discussion was tabled after it was pointed out that this had been attempted for years in SG1 and that we would need a well-thought concrete proposal to have a productive discussion on this. We then reviewed the executor polls intended for the 2020 Fall Library Evolution polling period. No major issues or concerns with the polls were identified.

OUTCOME: We will commence 2020 Fall Library Evolution polling as planned.

@brycelelbach
Copy link
Collaborator

@brycelelbach brycelelbach commented Dec 9, 2020

2020 Fall Library Evolution Polls

P2262: 2020 Fall Library Evolution Poll Outcomes

POLL 0: Remove implicit adaptation from P0443R14 (Executors) by applying P2235R0 to P0443R14, which will make schedule only take schedulers, make execute only take executors, make sender and receiver operations like connect only take senders and receivers, and add explicit adaptation from executor to scheduler (make_scheduler_from_executor) but not vice versa.

Strongly Favor Weakly Favor Neutral Weakly Against Strongly Against
21 15 0 0 0

Outcome: Unanimous consensus in favor.

POLL 1: Use one class for each individual trait instead of combined traits classes (sender_traits, etc) in P0443R14 (Executors).

Strongly Favor Weakly Favor Neutral Weakly Against Strongly Against
7 7 7 5 2

Outcome: No consensus.

POLL 2: Remove static_thread_pool from P0443R14 (Executors). It may be pursued in a follow-on proposal.

Strongly Favor Weakly Favor Neutral Weakly Against Strongly Against
8 11 4 7 2

Outcome: Weak consensus in favor.

POLL 3: Remove any_executor from P0443R14 (Executors). It may be pursued in a follow-on proposal.

Strongly Favor Weakly Favor Neutral Weakly Against Strongly Against
10 9 4 4 2

Outcome: Consensus in favor.

POLL 4: Remove any_executor::target and any_executor::target_type from P0443R14 (Executors).

Strongly Favor Weakly Favor Neutral Weakly Against Strongly Against
12 10 4 2 0

Outcome: Consensus in favor.

POLL 5: P0443R14 (Executors) is sufficiently mature that we should aim to ship it in C++23.

Strongly Favor Weakly Favor Neutral Weakly Against Strongly Against
10 12 7 10 1

Outcome: Weak consensus in favor.

Outcome

Revise P0443R14 (Executors) as follows and return to Library Evolution for further review:

  • Apply P2235R0.
  • Remove static_thread_pool. A separate follow-on proposal for static_thread_pool is encouraged.
  • Remove any_executor. If any_executor is pursued in the future, any_executor::target and any_executor::target_type shall be removed.

We will continue on our planned course of aiming to ship P0443R14 (Executors) in C++23, but a notable minority in Library Evolution are not convinced that P0443R14 (Executors) is sufficiently mature. Library Evolution wants to see more field experience with P0443R14 (Executors). P0443R14 (Executors) authors and advocates should take note of this. Focus on demonstrating field experience through implementations and usage, improving introductory material, minimizing the scope, resolving outstanding minor open issues, and developing wording to increase Library Evolution confidence in the maturity of P0443R14 (Executors).

We encourage a separate follow-on proposal exploring individual traits versus combined traits classes in general, using P0443R14 (Executors) as an example to gauge impact.

@jensmaurer jensmaurer removed this from the 2020-telecon milestone Dec 27, 2020
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
SG1 in Cologne 2019
Not Discussed
LEWGBelfast2019
Thursday Morning (Executors &amp; gen...
SG1 Prague
Tuesday
Linked pull requests

Successfully merging a pull request may close this issue.

None yet
7 participants
@brycelelbach @FabioFracassi @ogiroux @tituswinters @jensmaurer @wg21bot and others
You can’t perform that action at this time.