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Re: [SG14] SG14 Aug 12 meeting

From: Inbal Levi <sinbal2l_at_[hidden]>
Date: Thu, 13 Aug 2020 10:58:36 +0300
Thanks very much Ben, Staffan. Just a small clarification for ring buffer
update:
Inbal: Technical difficulties with ring buffer meeting yesterday.
Gathering the various inputs for the ring buffer. One option is to propose
some ring buffer (P0059) abilities to P1958 and P0260. Use cases are
welcome, so that we can decide if expanding P1958 is worthwhile. Jens
suggested a use case for a ring span, I have formed an initial API and
hoping to have his feedback on it.

On Wed, 12 Aug 2020 at 23:43, Patrice Roy via SG14 <sg14_at_[hidden]>
wrote:

> Thanks everyone, and special thanks to Ben. It's (almost) like being
> there! :)
>
> Le mer. 12 août 2020 à 15:35, Michael Wong via SG14 <sg14_at_[hidden]>
> a écrit :
>
>> Thank you all, especially to Staffen for chairing and Ben for taking
>> notes. So far our experiment of having each domain chair run meetings the
>> past 3 months have been working out very well, having done Games, Embedded,
>> and Finance. Thank you all.
>>
>> On Wed, Aug 12, 2020 at 3:25 PM Hubert Tong via SG14 <
>> sg14_at_[hidden]> wrote:
>>
>>> On Wed, Aug 12, 2020 at 2:58 PM Ben Craig via SG14 <
>>> sg14_at_[hidden]> wrote:
>>>
>>>> Minutes for today’s meeting…
>>>>
>>> Thanks Ben.
>>>
>>>
>>>>
>>>>
>>>> Ben Craig: Minutes
>>>>
>>>> Staffan Tjernstrom: Chair
>>>>
>>>> Michael Wong
>>>>
>>>> Arthur O'Dwyer
>>>>
>>>> Andrew Lumsdaine
>>>>
>>>> Basit Ayantunde
>>>>
>>>> Billy Baker
>>>>
>>>> connor horman
>>>>
>>>> Derek Haines
>>>>
>>>> Henry Miller
>>>>
>>>> Inbal Levi
>>>>
>>>> Maxime Laine
>>>>
>>>> Muklek Bokth Choudhury
>>>>
>>>> Robert Douglas
>>>>
>>>> Ronen Friedman
>>>>
>>>> Hubert Tong
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Wong: Inverted meetings: maybe once every three or four months while
>>>> coronavirus is going. CppCon now fully online. Kona meeting is in
>>>> Jeopardy. Bulgaria, is the next most likely F2F.
>>>>
>>>>
>>>>
>>>> Ben: Pitch I've heard is that 6 months after sports start is when we'll
>>>> have a new F2F
>>>>
>>>>
>>>>
>>>> Inbal: Virtual plenary is in the works
>>>>
>>>>
>>>>
>>>> Staffan: All we know is that we don't know.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Wong: Affinity was reviewed in SG1, good to move forward into LEWG.
>>>> Low level one needs more discussion. Now the paper is talking more about
>>>> interference patterns. Adjacency locality property work was discussed in
>>>> an inverted meeting.
>>>>
>>>>
>>>>
>>>> Staffan: I see us doing what needs to be done to get executors done,
>>>> maybe these will follow along.
>>>>
>>>>
>>>>
>>>> Inbal: Technical difficulties with ring buffer meeting yesterday.
>>>> Gathering the various inputs for ring buffer. May want to move some ring
>>>> buffer things from ring buffer paper to P1958 and P0260. Need use cases.
>>>> Jens suggested that this be a ring span.
>>>>
>>>>
>>>>
>>>> From Maxime Lainé to Everyone: 01:22 PM
>>>>
>>>> sure, but I can't see any more use cases as those already there sadly..
>>>> (perhaps something driver related for networking but seems a bit stretched
>>>> out)
>>>>
>>>>
>>>>
>>>> From Inbal Levi to Everyone: 01:25 PM
>>>>
>>>> Jens have suggested something along the lines of ring_span, so that's
>>>> one direction. But we need to figure out if Guy's popping-strategy (from
>>>> P0059) is something that is worth importing to P1958
>>>>
>>>>
>>>>
>>>> Staffan: LEWGI wasn't thrilled with P1958 interface, but didn't hate it
>>>> either. LEWGI wanted to see how things differed with ring buffer.
>>>>
>>>>
>>>>
>>>> Staffan: P0593 implicit object creation. Adopted in the core language
>>>> as a DR. start_lifetime_as isn't in the library yet. Very confident that
>>>> it will be in C++23.
>>>>
>>>>
>>>>
>>>> Staffan: P0593 is important to finance because of pipeline
>>>> applications, similar to niall's load / unload objects out of memory ideas.
>>>>
>>>>
>>>>
>>>> Hubert: std::launder won't help with the serialization things.
>>>>
>>> I think this needs:
>>> "in strict terms without ensuring that the lifetime of an appropriate
>>> object has started".
>>>
>>>
>>>> start_lifetime_as only lets you claim that there is an object, previous
>>>> references need to go through std::launder.
>>>>
>>>>
>>>>
>>>> Staffan: Probably wait to talk about member layout control until Rene
>>>> is able to make it on.
>>>>
>>>>
>>>>
>>>> Wong: September is probably the right time to reconnect with Renwick to
>>>> get forward progress on the paper and implementation.
>>>>
>>>>
>>>>
>>>> Inbal: Trying to summarize decisions that are made in the low cost
>>>> exception space for a cppcon talk.
>>>>
>>>>
>>>>
>>>> Ben: Paper in the works to discuss error handling tradeoffs. Will send
>>>> it to Wong and Inbal.
>>>>
>>>>
>>>>
>>>> Staffan: Big finance concern is just getting C++20 implemented and
>>>> seeing the impact, like with jthread and the sync primitives. Seeing real
>>>> at-scale impact with concepts and modules.
>>>>
>>>>
>>>>
>>>> Wong: How well does the networking proposal work for finance? Maybe
>>>> there's an RPC proposal?
>>>>
>>>>
>>>>
>>>> Staffan: Anything that helps low level timing stability or development
>>>> throughput is of interest. In finance, lots of people have the same idea
>>>> at about the same time, but only the first 50% of people or so will make
>>>> money on it.
>>>>
>>>>
>>>>
>>>> Wong: How do contracts feel in your space?
>>>>
>>>>
>>>>
>>>> Staffan: Vital, just not that everyone has realized that what they are
>>>> doing is contracts work.
>>>>
>>>>
>>>>
>>>> Wong: Bloomberg is largely doing it for verification.
>>>>
>>>>
>>>>
>>>> From Robert Douglas to Everyone: 01:46 PM
>>>>
>>>> Are there any papers in flight, that anyone is aware of, for attributes
>>>> for hot/cold, a-la likely/unlikely?
>>>>
>>>>
>>>>
>>>> Robert Douglas: gnu has hot / cold as well. Has anyone seen a paper
>>>> along those lines?
>>>>
>>>>
>>>>
>>>> Staffan: likely / unlikely don't strictly do that, it does help. Not
>>>> for data though.
>>>>
>>>>
>>>>
>>>> Staffan: finance ends up living in a weird world where the most common
>>>> things need to be marked "unlikely" for performance.
>>>>
>>>>
>>>>
>>>> From Me to Everyone: 01:50 PM
>>>>
>>>> Timur Doumler is also trying to drag an assume attribute back from
>>>> contracts
>>>>
>>>>
>>>>
>>>> From connor horman to Everyone: 01:52 PM
>>>>
>>>> I'd be interested in seeing that as well.
>>>>
>>>>
>>>>
>>>> Robert Douglas: I usually see this for error handling functions that
>>>> are marked both as unlikely and cold.
>>>>
>>>>
>>>>
>>>> Wong: Could use a paper exploring this.
>>>>
>>>>
>>>>
>>>> From Inbal Levi to Everyone: 01:53 PM
>>>>
>>>> Yes. But to my humble understanding, the support is vague.
>>>>
>>>>
>>>>
>>>> From Maxime Lainé to Everyone: 01:53 PM
>>>>
>>>> hot/cold pragmas/markers seems a bit out of language, more of a
>>>> compiler feature, but I'm open for discussion as well
>>>>
>>>>
>>>>
>>>> From Inbal Levi to Everyone: 01:53 PM
>>>>
>>>> P1774R3
>>>>
>>>>
>>>>
>>>> Staffan: Would like to have an offline discussion talking about hot /
>>>> cold.
>>>>
>>>>
>>>>
>>>> Actions:
>>>>
>>>> * Wong to talk with Renwick
>>>>
>>>> * Staffan + Robert to talk about object layout
>>>>
>>>> * Revisit object layout space when Rene is on the call
>>>>
>>>>
>>>>
>>>> *From:* SG14 <sg14-bounces_at_[hidden]> *On Behalf Of *Matthew
>>>> Butler via SG14
>>>> *Sent:* Wednesday, August 12, 2020 10:14 AM
>>>> *To:* Low Latency:Game Dev/Financial/Trading/Simulation/Embedded
>>>> Devices <sg14_at_[hidden]>
>>>> *Cc:* Matthew Butler <mbutler_at_[hidden]>
>>>> *Subject:* [EXTERNAL] Re: [SG14] SG14 Aug 12 meeting
>>>>
>>>>
>>>>
>>>> Me as well.
>>>>
>>>>
>>>>
>>>> On Wed, Aug 12, 2020 at 9:10 AM René Ferdinand Rivera Morell via SG14 <
>>>> sg14_at_[hidden]> wrote:
>>>>
>>>> Same for me.
>>>>
>>>> On Wed, Aug 12, 2020, 11:07 AM Guy Cpp via SG14 <sg14_at_[hidden]>
>>>> wrote:
>>>>
>>>> Apologies: I won't be able to attend this month's meeting. Have a great
>>>> time!
>>>>
>>>>
>>>>
>>>> Cheers,
>>>> G
>>>>
>>>>
>>>>
>>>> On Tue, 11 Aug 2020 at 17:06, Tjernstrom, Staffan via SG14 <
>>>> sg14_at_[hidden]> wrote:
>>>>
>>>> Topic: SG14 Low Latency Monthly
>>>>
>>>> This meeting is Finance focused and is chaired by Staffan Tjernström.
>>>>
>>>> Hi,
>>>>
>>>> Michael Wong is inviting you to a scheduled Zoom meeting.
>>>>
>>>> Topic: SG14 monthly Apr 2020-Oct 2020
>>>>
>>>> Time: Jun 11, 2020 02:00 AM Eastern Time (US and Canada) 6 UTC
>>>> Jun 11, 2020 02:00 AM 6UTC
>>>> Jul 8, 2020 02:00 PM 18 UTC
>>>> Aug 12, 2020 02:00 PM 18 UTC
>>>> Sep 9, 2020 02:00 PM 18 UTC
>>>> Oct 7, 2020 02:00 PM 18 UTC
>>>>
>>>> Join from PC, Mac, Linux, iOS or Android:
>>>>
>>>> Password: 013549
>>>>
>>>> Or iPhone one-tap :
>>>> US: +13462487799,,819108882# or +14086380968,,819108882#
>>>> Or Telephone:
>>>> Dial(for higher quality, dial a number based on your current
>>>> location):
>>>> US: +1 346 248 7799 or +1 408 638 0968 or +1 646 876 9923 or +1
>>>> 669 900 6833 or +1 253 215 8782 or +1 301 715 8592 or +1 312 626 6799
>>>> or 877 853 5247 (Toll Free)
>>>> Meeting ID: 819 108 882
>>>> Password: 013549
>>>> International numbers available: https://iso.zoom.us/u/abhaIjFKLZ
>>>> <https://urldefense.com/v3/__https:/iso.zoom.us/u/abhaIjFKLZ__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacLmXh7zK$>
>>>>
>>>> Or Skype for Business (Lync):
>>>> https://iso.zoom.us/skype/819108882
>>>> <https://urldefense.com/v3/__https:/iso.zoom.us/skype/819108882__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacEm5_qyh$>
>>>>
>>>> Agenda:
>>>>
>>>> 1. Opening and introductions
>>>>
>>>> 1.1 Roll call of participants
>>>>
>>>> 1.2 Adopt agenda
>>>>
>>>> 1.3 Approve minutes from previous meeting, and approve publishing
>>>> previously approved minutes to ISOCPP.org
>>>>
>>>> 1.4 Action items from previous meetings
>>>>
>>>> 2. Main issues (125 min)
>>>>
>>>> 2.1 General logistics
>>>>
>>>> Inverted meeting frequency?
>>>>
>>>> CPPCON logistics
>>>> CPPCON Embedded Track: Ben Saks
>>>> future C++ Standard meetings:
>>>>
>>>> 2.2 Paper reviews
>>>>
>>>> 2.2.1 any other proposal for reviews?
>>>>
>>>> SG14/SG19 features/issues/defects:
>>>>
>>>>
>>>> https://docs.google.com/spreadsheets/d/1JnUJBO72QVURttkKr7gn0_WjP--P0vAne8JBfzbRiy0/edit#gid=0
>>>> <https://urldefense.com/v3/__https:/docs.google.com/spreadsheets/d/1JnUJBO72QVURttkKr7gn0_WjP--P0vAne8JBfzbRiy0/edit*gid=0__;Iw!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacAwLxEYi$>
>>>>
>>>> These are more status updates than full-blown reviews this time around.
>>>>
>>>> Affinity https://github.com/cplusplus/papers/issues?q=is:issue+P1436
>>>> <https://urldefense.com/v3/__https:/github.com/cplusplus/papers/issues?q=is:issue*P1436__;Kw!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacEOd4ruZ$>
>>>>
>>>> System topology discovery
>>>> https://github.com/cplusplus/papers/issues?q=is:issue+P1795
>>>> <https://urldefense.com/v3/__https:/github.com/cplusplus/papers/issues?q=is:issue*P1795__;Kw!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacG9gxIRs$>
>>>>
>>>> Ring Buffer https://github.com/cplusplus/papers/issues?q=is:issue+P0059
>>>> <https://urldefense.com/v3/__https:/github.com/cplusplus/papers/issues?q=is:issue*P0059__;Kw!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacAETJvyX$>
>>>>
>>>> Object Creation
>>>> https://github.com/cplusplus/papers/issues?q=is:issue+P0593
>>>> <https://urldefense.com/v3/__https:/github.com/cplusplus/papers/issues?q=is:issue*P0593__;Kw!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacM7wUnzd$>
>>>>
>>>> Member layout control
>>>> https://github.com/cplusplus/papers/issues?q=is:issue+P1605
>>>> <https://urldefense.com/v3/__https:/github.com/cplusplus/papers/issues?q=is:issue*P1605__;Kw!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacFPftyFn$>
>>>>
>>>> Discuss future direction of detreministic C++ exception group :
>>>>
>>>> Low-cost Deterministic C++ Exceptions for Embedded Systems
>>>> <
>>>>
>>>> https://www.research.ed.ac.uk/portal/files/78829292/low_cost_deterministic_C_exceptions_for_embedded_systems.pdf
>>>> <https://urldefense.com/v3/__https:/www.research.ed.ac.uk/portal/files/78829292/low_cost_deterministic_C_exceptions_for_embedded_systems.pdf__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacHGnA89n$>>
>>>>
>>>>
>>>> Low-cost
>>>> Deterministic C++ Exceptions for Embedded Systems James Renwick James
>>>> Renwick et al.
>>>>
>>>> 2.3 Domain-specific discussions
>>>>
>>>> 2.3.1 SIG chairs
>>>>
>>>> - Embedded Programming chairs: Ben Craig, Wouter van Ooijen and Odin
>>>> Holmes, John McFarlane
>>>>
>>>> - Financial/Trading chairs: Staffan Tjernström, Carl Cooke, Neal
>>>> Horlock,
>>>> Mateusz Pusz, Clay Trychta,
>>>> - Games chairs: Rene Riviera, Guy Davidson and Paul Hampson
>>>> - Linear Algebra chairs: Bob Steagall, Mark Hoemmen, Guy Davidson
>>>>
>>>> 2.4 Other Papers and proposals
>>>>
>>>> 2.5 Future F2F meetings:
>>>>
>>>> 2.6 future C++ Standard meetings:
>>>> https://isocpp.org/std/meetings-and-participation/upcoming-meetings
>>>> <https://urldefense.com/v3/__https:/isocpp.org/std/meetings-and-participation/upcoming-meetings__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacH7nNQQe$>
>>>>
>>>> - 2020-11: (New York, tentative) Cancelled.
>>>> - 2021-02-22 to 27: Kona, HI, USA
>>>>
>>>> 3. Any other business
>>>> Reflector
>>>> https://lists.isocpp.org/mailman/listinfo.cgi/sg14
>>>> <https://urldefense.com/v3/__https:/lists.isocpp.org/mailman/listinfo.cgi/sg14__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacAJ8MqKp$>
>>>> As well as look through papers marked "SG14" in recent standards
>>>> committee
>>>> paper mailings:
>>>> http://open-std.org/jtc1/sc22/wg21/docs/papers/2015/
>>>> <https://urldefense.com/v3/__http:/open-std.org/jtc1/sc22/wg21/docs/papers/2015/__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacK1x_akR$>
>>>> http://open-std.org/jtc1/sc22/wg21/docs/papers/2016/
>>>> <https://urldefense.com/v3/__http:/open-std.org/jtc1/sc22/wg21/docs/papers/2016/__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacGaC9T9_$>
>>>>
>>>> Code and proposal Staging area
>>>> https://github.com/WG21-SG14/SG14
>>>> <https://urldefense.com/v3/__https:/github.com/WG21-SG14/SG14__;!!FbZ0ZwI3Qg!-Cx7ecFH_AJfg5_2VUHA4q_4m6HrgQCiCUI56OFLF7QJGeMDjmTacJ4nXJap$>
>>>> 4. Review
>>>>
>>>> 4.1 Review and approve resolutions and issues [e.g., changes to SG's
>>>> working draft]
>>>>
>>>> 4.2 Review action items (5 min)
>>>>
>>>> 5. Closing process
>>>>
>>>> 5.1 Establish next agenda
>>>>
>>>> 5.2 Future meeting
>>>>
>>>> Time: Sep 9, 2020 02:00 PM Eastern Time (US and Canada) : Security:
>>>> Mathew
>>>> Butler
>>>>
>>>> Time: Oct 14, 2020 02:00 PM Eastern Time (US and Canada): Games: Rene
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Kind Rgds
>>>>
>>>> Staffan Tj.
>>>>
>>>> pp Michael Wong
>>>>
>>>>
>>>>
>>>>
>>>> ------------------------------
>>>>
>>>>
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>>>>
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>>>>
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>>>>
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>>>>
>>> _______________________________________________
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>>>
>> _______________________________________________
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>>
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Received on 2020-08-13 03:02:13