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
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>
> 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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