Meeting notes.

On Tue, Apr 13, 2021 at 10:53 AM Michael Wong <> wrote:

Topic: SG14 Low Latency Monthly

This meeting is focused on Finance/Low latency. 


Michael Wong is inviting you to a scheduled Zoom meeting.

Topic: SG14 monthly 
Time: 2nd Wednesdays 02:00 PM Eastern Time 1800 UTC (US and Canada)
    Every month on the Second Wed, 
    Apr 14, 2020 02:00 PM 1800 UTC
    May 12, 2021 02:00 PM 1800 UTC
    June 9, 2021 02:00 PM 1800 UTC

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1. Opening and introduction

ISO Code of Conduct

ISO patent policy.

WG21 Code of COnduct:

1.1 Roll call of participants

Andreas Weis, Ben Saks, Billy Baker, Conor Horman, Henry Miller, Jakob Lovhall, Michael Adams, Piotr Grygorczuk, Puya Daravi, Rene Ferdinand Rivera Morell, Ronan Keryell, Sean Middleditch, Sophia Porier, Jeffrey Olkin, Matthew Butler, Michael Wong, Jens Maurer , Guy Davidson, Max Gardner, John McFarlane

1.2 Adopt agenda

1.3 Approve minutes from previous meeting, and approve publishing
 previously approved minutes to

1.4 Action items from previous meetings

2. Main issues (125 min)

2.1 General logistics

Future meeting plans

    Apr 14, 2020 02:00 PM ET/1800 UTC: Finance focus on low latency

    May 12, 2021 02:00 PM ET/1800UTC: Games
    June 9, 2021 02:00 PM ET/1800 UTC: Embedded

2.2 Paper reviews

Compound assignment review

thank Wouter and SG14 in acknowledgment

intro should say embedded community (who never update their 3rd party header) that was overlooked in initial review which focused on SG1
so a different interface will not fix the problem for future
some compatibility layer from vendors for future? that is a future proposal

make sure += does not appear from header analysis

mixed C and C++ impact: add SG22 lukewam reception
also porting of C to C++ impact

restore status quo in existence for 30 years

[depr.volatile.type] annex might need to be updated

de-deprecate is split in 3.2 make it a newline

Low Latency topic brainstorm

fpga offload computation suing VHDL/verilog 
nanosecond resolution, lock free programming
low latency, control of generated assembly
can I access hardware features, memory card, 
C like subset of C++ for this,
memory barriers 
no support for I/O control, DMA memory, whether device is there, but these  may be out of scope

what does low latency mean? is it an upper bound? is it determinism?

also need thread priorities Patrice roy
also need cache controlling
also needing scheduling periodic thread intervals, by some deadline (flagging a real-time thread, deal with conflicts)
get a processor onto a cpu when its idle
we also need cpu pinning, like madvise
also mange memory mapped files carefully,
but most of these are owned by the OS

standardize filesystem, but many freestanding systems that don't have this, offer standard cross platform apis for this, is there standard policy for this
support some real time thread with a deadline, allows you to associate n-number of threads as working on same real time constraint, grouping api 
should we add threading attribute that support this
Vulkan has a capability model, standard model, but capability fits specific hardware
standard api to query capability

use encoding like unicode api

what about Os vs bare metal / library only profiles

conditionally support is a kind of segmentation already
concern about SQL profiles which seem to fail
features with non-local 
vft,  I asked for it so thats ok
embedded small devices stuck with C89, 

similar for templates which don't generate object code 

we have compilers that have flags to subset; this leaves people out in the cold and segmented language, hwo to help a single C++ instead of subset dialects 

floating point hardware is not needed for floating point, avoid use at runtime with a lookup table

annotate and enforce real-time constraint on a call path to say a function needs real-time, or trap at runtime if unable to satisfy; say threads is allowed or not allowed to call synchronous apis but aim to fail early 


2.2.1 any other proposal for reviews?

SG14/SG19 features/issues/defects:

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
   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:


3. Any other business
As well as look through papers marked "SG14" in recent standards committee
paper mailings:

Code and proposal Staging area
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

      Apr 14, 2020 02:00 PM 1800 UTC
    May 12, 2021 02:00 PM 1800 UTC
    June 9, 2021 02:00 PM 1800 UTC  

Kind Rgds