P2066 Suggested draft TS for C++ Extensions for Transaction Memory Light

[wg21bot]

P2066R0 Suggested draft TS for C++ Extensions for Transaction Memory Light (Jens Maurer, Michael L. Scott)

[jfbastien]

Let's have SG1 take a look first, then forward to EWG.

[ogiroux]

SG1 in Prague

We will see this again in Varna

[wg21bot]

P2066R1 Suggested draft TS for C++ Extensions for Transaction Memory Light (Jens Maurer, Hans Boehm, Victor Luchangco, Michael L. Scott, Michael Spear, and Michael Wong)

[wg21bot]

P2066R2 Suggested draft TS for C++ Extensions for Transaction Memory Light (Jens Maurer, Hans Boehm, Victor Luchangco, Michael L. Scott, Michael Spear, and Michael Wong)

[ogiroux]

SG1 approves the design and wording of P2066R2 targeting the next
revision of the TM TS (which is not expected to be reaffirmed in its
earlier form).
No objection to unanimous consent. (15 people attending)

[jensmaurer]

This contains no library changes, but only core language changes, and thus should go to EWG next.

[jfbastien]

This was discussed in EWG telecon today.

Use a/many (potentially contextual) keyword to denote atomic blocks, rather than making it a library feature. For example atomic do { ... }.

SF	F	N	A	SA
5	8	1	0	0

The proposed approach to TM generally seems acceptable, and would fit in a TM TS v2.

SF	F	N	A	SA
3	12	1	0	0

We'll see it again after discussing the particular keyword approach. LEWG should also see it to discuss library support guarantees, if any.

[wg21bot]

P2066R3 Suggested draft TS for C++ Extensions for Transaction Memory Light (Jens Maurer, Hans Boehm, Victor Luchangco, Michael L. Scott, Michael Spear, and Michael Wong)

[cor3ntin]

Mailing list discussion (2021-04-26 2021-06-14)

• Very little discussion
• Please make sure the paper contains and conserves motivation and design discussion
• Please make sure the list of libraries features supported in atomic blocks is detailed, in particular, consider whether locale should be exluded (CF the EWG meeting minutes)

[wg21bot]

P2066R8 Suggested draft TS for C++ Extensions for Minimal Transactional Memory (Jens Maurer, Hans Boehm, Victor Luchangco, Michael L. Scott, Michael Spear, and Michael Wong)

[jfbastien]

EWG poll results from https://wg21.link/P1018R13

🗳 Poll: Forward P2066r7 "Suggested draft TS for C++ Extensions for Transaction Memory Light" to Core to become the Transactional Memory TS v2.

SF	F	N	A	SA
6	12	3	0	1

Poll outcome: ✅ consensus.

[brycelelbach]

We determined that Library Evolution didn't need to look at this.

[jfbastien]

Adding LWG to make sure they OK the tiny library bits:

16.4.6.17 Functions usable in an atomic block [atomic.use]

[jensmaurer]

CWG 2021-09-14: Approved for D2066R9 plenary vote; awaiting LWG approval.
https://wiki.edg.com/pub/Wg21telecons2021/SG5/d2066r9.html

[JeffGarland]

LWG reviewed and approved with small updates on 2021-09-17 telecon.

https://wiki.edg.com/bin/view/Wg21telecons2021/P2066-20210917

poll: Library approves of the changes to the Library clauses

F	A	N
9	0	1

[wg21bot]

P2066R9 Suggested draft TS for C++ Extensions for Minimal Transactional Memory (Jens Maurer, Hans Boehm, Victor Luchangco, Michael L. Scott, Michael Spear, and Michael Wong)

[wg21bot]

P2066R10 Suggested draft TS for C++ Extensions for Minimal Transactional Memory (Jens Maurer, Hans Boehm, Victor Luchangco, Michael L. Scott, Michael Spear, and Michael Wong)

[jensmaurer]

Approved 2021-10.