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Subject: Re: June 11 SG14 6 UTC Inverted meeting (Games)
From: Michael Wong (fraggamuffin_at_[hidden])
Date: 2020-06-16 11:59:42


Thanks Matthew for the linnks. Here are the minutes from June SG14 call.
Thanks also to Matthew for the minutes:

No objections to previous minutes
No action items from prev meeting

Cppcon:
will go ahead, online/offline ratio undecided
sg14 face to face cppcon will not happen, will have regular online
meetup instead
submissions still (sort of) open
reviewers for papers for embedded track appreciated

Future CPP standard meetings:
ISO & Insights have put face-to-face meetings on hold for moment
Currently moratorium on forwarding papers on, but may not continue due
to length of covid lockdowns

Papers:

Colony:
Wording is progressing with help from Jens
Question around having reserve function - whether necessary:
- not present in deque
- performance detriment when present in previous benchmarks (for full
reserve implementation)
- question whether necessary regarding shifting allocation out of hot
loop code - suggestion that this is solved to an extent via allocators
when this is necessary
- also question around whether is necessary to stop colony from
allocating lots of small memory blocks when the rough number of total
elements is known in advance - suggestion that this is solved by
adjusting minimum block capacities
- suggestion that we can always add this later in standardization process
- inclusion may force necessity of another function to free up unused
memory blocks - as opposed to shrink_to_fit, which is not required to
keep iterators to elements valid
- retaining memory blocks where all elements have been erased - could
be problematic in terms of creating uncertainty for developers as to
whether a memory block is freed
- question for later paper revision - should shrink_to_fit consolidate
container and remove skips, or reallocate elements to maximum capacity
blocks and create best-case cache locality

Question around supplying min/max block capacity limits to
constructors/functions - whether invalid (out-of-range) supplied
limits should be silently corrected, or if functions should
throw/return an error code/some combination of these:
- Constructors can throw anyway, so throwing or defining as UB most logical
- Settle for throwing as more straightforward
- Is skipfield necessary - seems to be for any future implementation
- Nathaniel Niel's suggestion of alternative index - unclear as to
what implementation would be - may get back to Matt later

Affinity:
New paper, 2155, following on from 1436
Summary of changes
Overview:
- p1436 -executor-centric with hints - required knowledge of
abstraction of executor
- Switch to algorithmic-centric properties - describes what freedoms
implementation has, semantics of algorithm
- Can be applied more generically to more executors
- Executor properties + execution policy properties
- Algorithm can execute what user is requesting based on executor's
hardware abstraction
- Definition of 'locality interference' - metric

Jens wording critique:
- should contain editorial instruction that this should apply on top of
p0443
- virtual machines/GPU's/explicit hardware descriptions do not fit
within C++ abstract machine, should be moved to proposal
- 'bulk algorithm' concept/word is not existing word in C++ standard,
needs explicit explanation if used
- 'must' too ambiguous, use 'shall'. 'should' similarly cannot be used
- only italicize terms when defining them, not elsewhere
- 'higher constructive interference' not defined, 'hardware
constructive interference' is
- changes/additions to abstract machine potentially affects ability of
compiler to optimize
- work items needs explaining

CPP deterministic exception group: nothing
Embedded: Nothing to report
Financial: nobody present
Games: Linear algebra reviewing next week in LEWG online, BLAS &
operator overload, 1500 UTC monday
Kona is next CPP standards meeting in line

Paul: Is there a face-to-face SG14 in november for MeetingCPP? Unlikely as
it will be virtual but may be the next Israel F2F meeting.

 Agenda
item for next meeting.

On Wed, Jun 10, 2020 at 6:08 PM Matthew Bentley via SG14 <
sg14_at_[hidden]> wrote:

> Hi Michael,
> just to update the current proposal for colony is at:
>
> https://htmlpreview.github.io/?https://github.com/WG21-SG14/SG14/blob/master/Docs/Proposals/D0447R11%20-%20Introduction%20of%20colony%20to%20the%20Standard%20Library.html
>
> Still going through some revisions before re-submitting at the moment.
>
>
> On Thu, 11 Jun 2020 at 07:30, Michael Wong via SG14 <sg14_at_[hidden]>
> wrote:
>
>> Updated slides affinity:
>>
>> https://docs.google.com/presentation/d/1V_69toBb1mF1a_8cRH3G_TkE1EOekW95Jz0LB4o_lTc/edit#slide=id.p4
>>
>> On Tue, Jun 9, 2020 at 10:14 PM Michael Wong <fraggamuffin_at_[hidden]>
>> wrote:
>>
>>> Topic: SG14 Low Latency Monthly.
>>>
>>> This meeting is Games focused and is chaired by Guy Davidson.
>>>
>>> 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:
>>> https://iso.zoom.us/j/819108882?pwd=L0pPZm5QRWlTYXdJditvU1JLdjFYUT09
>>> 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
>>>
>>> Or Skype for Business (Lync):
>>> https://iso.zoom.us/skype/819108882
>>>
>>> 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 issue
>>>
>>> s (125 min)
>>>
>>> 2.1 General logistics
>>> CPPCON logistics
>>> CPPCON SG14 plans
>>> CPPCON Embedded Track: Ben Saks
>>> future C++ Standard meetings:
>>>
>>> 2.2 Paper reviews
>>>
>>> 1. Colony by Matthew Bentley,
>>> Colony Matthew Bentley https://wg21.link/P0447
>>>
>>> 2. Affinity by Gordon Brown al:
>>>
>>> Affinity Gordon Brown, Ruyman Reyes, Michael Wong, Mark Hoemmen, Jeff
>>> Hammond, Tom Scogland, Domagoj Šarić https://wg21.link/p1436
>>>
>>> 2.2.1 any other proposal for reviews?
>>>
>>> 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>
>>>
>>>
>>> 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
>>> <
>>>
>>> http://wiki.edg.com/bin/edit/Wg21belfast/McFarlane?topicparent=Wg21belfast.SG14CPPCON2019-09-17;nowysiwyg=1>
>>>
>>>
>>> - Financial/Trading chairs: Stephan TJ, 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
>>>
>>> - 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
>>> As well as look through papers marked "SG14" in recent standards
>>> committee
>>> paper 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 area
>>> https://github.com/WG21-SG14/SG14
>>> 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: Jul 8, 2020 02:00 PM Eastern Time (US and Canada) : Embedded: Ben
>>> Craig
>>>
>>> Time: Aug 12, 2020 02:00 PM Eastern Time (US and Canada) : Fiinance:
>>> Jens,
>>> Stephan
>>>
>>> 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
>>>
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