Topic: SG14 Low Latency Monthly This meeting is focused on Embedded.Hi,Michael Wong is inviting you to a scheduled Zoom meeting.Topic: SG14 monthlyTime: 2nd Wednesdays 02:00 PM Eastern Time 1900 UTC (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
Paul Bendixen, Andreas Weis, Brett Searles, Detlef Vollmann, Henry Miller, John McFarlane, Ka Ming Chan, Matthew Butler, Ronen Friedman, Michael Wong, Rene Riviera, Ben Saks, Andew Lumsdaine
1.2 Adopt agenda
SG13 events handling for graphics
event handling is low latency related, interrupt handler,
1.3 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 logisticsFuture meeting plans*Mar 9, 2022 02:00 PM ET/1900 UTC: Embedded**Apr 13,
2022 02:00 PM ET/1800 UTC: Finance/Low Latency
*May 11, 2022 02:00 PM ET/1800 UTC: Games
*June 8, 2022 02:00 PM ET/1800 UTC: Embedded
*Jul 13, 2022 02:00 PM ET/1800 UTC: Finance/Low Latency
*Aug 10, 2022 02:00 PM ET/1800 UTC: Games
*Sep 12, 2022 02:00 PM ET/1800 UTC: Embedded
*Oct 12, 2022 02:00 PM ET/1800 UTC: Finance/Low Latency
CPPCON:Sep 12
Embo++ is virtual and is free and can have GatherTown: Mar 25/26
free tickets may run out
Review latest mailings:
P2532 Removing exception_ptr from the receivers concept
design change now that executor is not in
if sender use excewptions, the nreceiver must habdle exceptions, but if noexcept sender then receiver has none
So for embedded if we dont have exceptions, then this would be maskable interrupts so it wont be handled
is it UDP? sender/receiver is much lower level
More redesigns likely for executors, should we have an SG for executors, but currently it was in SG1
sender/received supports events
Based on the last meeting and the discussions here.
P2544 C++ Exceptions are becoming more and more problematic
multi core systems with locks in the exception mechanism has severe penalties
need global lock on the unwinding table so as to be safe for when you load dynamic library even though it is rare you need the, unless you use transactional memory which could be an ABI break even if we use advance Lock free mechnisms
its the auxiliary data structure that the unwind mechanisms
can we put these tables in data segment instead of code segment?
changing the eh mechnism requires substantial knowledge to get it right
James Renwick and Bjarne should have a look at this
We might want to chime in here.
/Paul
P. S. P2327 de-deprecating volatile received a "consensus" straw poll.
started from SG14 and was accepted
P2327 straw poll consensus as a defect report to go in for 23, only the bitwise operator for volatile and people were surprised it is not atomic
original paper was still good because volatile is not to be used on multiple threads, but for hardware register arithmetic
Discussion on Low Latency/Finance topicsP2300SwiftDiscussion about Games topics: P2388R1 - Minimum Contract Support: either Ignore or Check_and_abort<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2388r1.html>Patrice's WIP on Games issues.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: Staffan TjernstrÃmCarl 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 9, 2022 02:00 PM ET/1900 UTC: Embedded* *Apr 13, 2022 02:00 PM ET/1800 UTC: Finance/Low Latency
*May 11, 2022 02:00 PM ET/1800 UTC: Games
*June 8, 2022 02:00 PM ET/1800 UTC: Embedded
*Jul 13, 2022 02:00 PM ET/1800 UTC: Finance/Low Latency
*Aug 10, 2022 02:00 PM ET/1800 UTC: Games
*Sep 12, 2022 02:00 PM ET/1800 UTC: Embedded
*Oct 12, 2022 02:00 PM ET/1800 UTC: Finance/Low Latency