Topic: SG14 Low Latency Monthly This meeting is focused on Finance/Low Latency though we can continue with the Games paper thatwas started in January, depending on what other papers or topics are ofinterest.I am also looking for a finance Subgroup chair. Thank you.Hi,Michael Wong is inviting you to a scheduled Zoom meeting.Topic: SG14 monthlyTime: 2nd Wednesdays 02:00 PM Eastern Time (US and Canada) Every month on the Second Wed,Join from PC, Mac, Linux, iOS or Android:https://iso.zoom.us/j/93151864365?pwd=aDhOcDNWd2NWdTJuT1loeXpKbTcydz09 Password: 789626Or iPhone one-tap : US: +12532158782,,93151864365# or +13017158592,,93151864365#Or Telephone: Dial(for higher quality, dial a number based on your current location): US: +1 253 215 8782 or +1 301 715 8592 or +1 312 626 6799 or +1346 248 7799 or +1 408 638 0968 or +1 646 876 9923 or +1 669 900 6833 or 877 853 5247 (Toll Free) Meeting ID: 931 5186 4365 Password: 789626 International numbers available: https://iso.zoom.us/u/abRrVivZoDOr Skype for Business (Lync): https://iso.zoom.us/skype/93151864365Agenda:1. Opening and introductionISO Code of Conduct<https://isotc.iso.org/livelink/livelink?func=ll&objId=20882226&objAction=Open&nexturl=%2Flivelink%2Flivelink%3Ffunc%3Dll%26objId%3D20158641%26objAction%3Dbrowse%26viewType%3D1*>*ISO patent policy.https://isotc.iso.org/livelink/livelink/fetch/2000/2122/3770791/Common_Policy.htm?nodeid=6344764&vernum=-2IEC Code of Conduct:https://www.iec.ch/basecamp/iec-code-conduct-technical-workWG21 Code of Conduct:https://isocpp.org/std/standing-documents/sd-4-wg21-practices-and-procedures1.1 Roll call of participants
Guy Davidson, John McFarlane, Patrice Roy
Arhtur O'Dwyer, Jake Fevold, Matthew Butler, Rene Morell, Ronen Friedman, Michael Wong, Andrew Drakeford
Jens Maurer, Brett Searles, Matthew Bentley
1.2 Adopt agenda1.3 Approve minutes from previous meeting, and approve publishing previously approved minutes to ISOCPP.org1.4 Action items from previous meetings2. Main issues (125 min)2.1 General logisticsVarna F2FC++23 and C++26 status
cppcon sg14? maybe
Future meeting plans*Mar 8, 2023 02:00 PM ET: Embedded*Apr 12, 2023
02:00 PM ET: Cancelled
* May 10, 2023
02:00 PM ET: Cancelled
* June 14, 2023
02:00 PM ET: Cancelled
* July 12, 2023
02:00 PM ET: Finance
* Aug 9, 2023
02:00 PM ET: Games
* Sep 12, 2023
02:00 PM ET: Embedded
* Oct 1: CPPCON
* Oct 10, 2023
02:00 PM ET: Finance
*Nov 8, 2023
02:00 PM ET: Kona F2F (Cancelled)
* Dec 12, 2023
02:00 PM ET: Games2.2 Paper reviewsDiscussion on Embedded:Review latest mailings:P2532 Removing exception_ptr from the receivers conceptBased on the last meeting and the discussions here.P2544 C++ Exceptions are becoming more and more problematicWe might want to chime in here./PaulP. S. P2327 de-deprecating volatile received a "consensus" straw poll.Discussion on Low Latency/Finance topicshttp://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p1839r4.pdfPatrice's paper on games.
Arthur O has 2 papers for flatmap and flatset is going to R1
omnibus paper, first 6 sections went to LWG directly
No content in this paper, just a feasibility study as to which feature we want to pursue. This will break into many smaller actual papers
This paper is attached to this thread.
EASTL to address allocation alignment issues of original STL
today, dont rewrite vector and change semantics,
Need flatmap/set/hive/ring buffer
anything that allocates without explicit action is frowned upon, because it affects framework, more about latency, PS and PC sorting algorithms, random number algo varies and lacks determinism
allocation determinism is how long, and is latency
random number determinism is same number from same seed;RNG engines are supposed to be deterministic in the standard.
(RNG determinism is mentioned in p1932.)
Distributions not so much.
requirements of games dev
speaking of "third-party STLs": There's a guy spending this summer to add P1144 trivial relocation to HPX Stellar!
Latency rather than predictability
Performance = how long it takes to get a set amount of work done (in practice)
Latency = the variability in terms of how long it takes to get the work done
In my view
RF:Ceph (my project, in the Storage realm) uses intrusive containers extensively
a multi-index container based on intrusive c is just being added to my part of the code
AO: an (intrusive or std) list is a sequence container, whereas hive (as currently proposed) is not — there's no way to insert into an arbitrary position in a hive, like you can into a list.
My variant of hive now supports emplace_back and emplace_front, because they're always cheap; but you physically can't support emplace(pos, args...)
Matthew Bentley talks about his paper PLF orderase
swap and pop behaviour
move and pop based on static and inplace vector
benchmarked it and got really fast single erasure, also fast for ranged erasure
anyone interested in collaborating on this paper no throw movable and nothrow copyable can just move/copy the back; great for deque and vectors (order matters)
what if order doesn't matter? Not necessary e.g. simd, 16 elements would just move from the back and preserve contagiousness and not suffer cost of copying everything back
asking for helpers on this paper.
When you `std::unstable_erase(myDeque, 42)`, should the implementation swap-and-pop-front, or swap-and-pop-back? Depends on the surrounding workload.? does back by default
6 going forward
1 not forward
Finance topics from July 14, 2021.https://lists.isocpp.org/sg14/2021/06/0636.phphttps://lists.isocpp.org/sg14/2021/07/0642.php2.2.1 any other proposal for reviews?Deterministic Exception for Embedded by James Renwickhttps://www.pure.ed.ac.uk/ws/portalfiles/portal/78829292/low_cost_deterministic_C_exceptions_for_embedded_systems.pdfFreestanding?SG14/SG19 features/issues/defects:https://docs.google.com/spreadsheets/d/1JnUJBO72QVURttkKr7gn0_WjP--P0vAne8JBfzbRiy0/edit#gid=02.3 Domain-specific discussions2.3.1 SIG chairs - Embedded Programming chairs: Ben Craig, Wouter van Ooijen and Odin Holmes, John McFarlane - Financial/Trading chairs: Carl Cooke, Neal Horlock, - Games chairs: Rene Riviera, Guy Davidson and Paul Hampson, Patrice Roy - Linear Algebra chairs: Bob Steagall, Mark Hoemmen, Guy Davidson2.4 Other Papers and proposals2.5 Future F2F meetings:2.6 future C++ Standard meetings:https://isocpp.org/std/meetings-and-participation/upcoming-meetings-3. Any other businessReflectorhttps://lists.isocpp.org/mailman/listinfo.cgi/sg14As well as look through papers marked "SG14" in recent standards committeepaper mailings:http://open-std.org/jtc1/sc22/wg21/docs/papers/2015/http://open-std.org/jtc1/sc22/wg21/docs/papers/2016/Code and proposal Staging areahttps://github.com/WG21-SG14/SG144. Review4.1 Review and approve resolutions and issues [e.g., changes to SG'sworking draft]4.2 Review action items (5 min)5. Closing process5.1 Establish next agenda5.2 Future meeting*Mar 8, 2023 02:00 PM ET: Embedded*Apr 12, 2023 02:00 PM ET: Cancelled
* May 10, 2023 02:00 PM ET: Cancelled
* June 14, 2023 02:00 PM ET: Cancelled
* July 12, 2023 02:00 PM ET: Finance
* Aug 9, 2023 02:00 PM ET: Games
* Sep 12, 2023 02:00 PM ET: Embedded
* Oct 1: CPPCON
* Oct 10, 2023 02:00 PM ET: Finance
*Nov 8, 2023 02:00 PM ET: Kona F2F Cancelled
* Dec 12, 2023 02:00 PM ET: Games