Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c++ > #87751

Re: An argument *against* (the liberal use of) references

From Paavo Helde <eesnimi@osa.pri.ee>
Newsgroups comp.lang.c++
Subject Re: An argument *against* (the liberal use of) references
Date 2022-12-08 13:38 +0200
Organization A noiseless patient Spider
Message-ID <tmsibg$rsmp$1@dont-email.me> (permalink)
References (7 earlier) <tm9khr$2oi11$3@dont-email.me> <tmn9fl$1kpl$1@gioia.aioe.org> <tmo8ho$ahd1$1@dont-email.me> <tmpl1b$1pke$1@gioia.aioe.org> <tmqu6c$kv25$1@dont-email.me>

Show all headers | View raw

07.12.2022 22:48 Chris M. Thomasson kirjutas:
> On 12/7/2022 1:05 AM, Juha Nieminen wrote:
> 
> 
>> If code that takes 0.01% of the total runtime
>> gets 1% slower... how much will it slow down the overall program?
>> Do the math.

My aim is to allow the program to scale safely to many-core machines. 
Even if some synchronization overhead is small today when running on 10 
cores in parallel, it does not mean it will remain small when run on a 
100-core or 1000-core machine, in some not so distant future.

> RCU beats them all, it is memory barrier free, well except for systems 
> that _need_ a membar for data-dependent loads, ala dec alpha. Iirc, 
> SPARC in RMO mode does not even need membars for such loads. Proxy 
> collection does pretty damn good, but not as good as RCU...
> 
> The membars take a big toll, especially the god damn #StoreLoad barrier 
> in SMR (aka, hazard pointers).

My current approach is to use single-threaded data structures as much as 
possible, so that the running threads would not disturb each other at 
all. But this creates other challenges like a need for deep copies, and 
a need to recalculate same things in different threads, on those copies.

It looks like if I want to use another approach with keeping more data 
in shared use I will indeed need to learn more about atomics and RCU.

Back to comp.lang.c++ | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-11-22 09:52 +0000
  Re: An argument *against* (the liberal use of) references "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2022-11-22 11:23 +0100
  Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-11-22 13:27 +0200
    Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-11-23 06:52 +0000
      Re: An argument *against* (the liberal use of) references "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-11-23 13:51 +0100
        Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-11-23 13:46 +0000
          Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-11-30 13:59 +0200
            Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-01 06:45 +0000
              Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 09:19 +0200
                Re: An argument *against* (the liberal use of) references Stuart Redmann <DerTopper@web.de> - 2022-12-01 14:06 +0100
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 16:45 +0200
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-01 16:02 +0000
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 20:21 +0200
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-01 19:09 +0000
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-02 05:53 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-02 14:36 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 12:29 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-02 20:55 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 12:58 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-02 21:18 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 14:16 -0800
                Re: An argument *against* (the liberal use of) references Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2022-12-02 21:09 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 13:22 -0800
                Re: An argument *against* (the liberal use of) references Branimir Maksimovic <branimir.maksimovic@icloud.com> - 2022-12-02 21:36 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-02 14:13 -0800
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-02 18:33 +0200
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-01 11:59 -0800
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-01 23:53 +0200
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-02 04:11 -0800
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-01 12:21 -0800
                Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-06 11:36 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-06 12:26 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-06 20:39 +0000
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-06 23:53 +0200
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-06 13:59 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-06 22:04 +0000
                Re: An argument *against* (the liberal use of) references Öö Tiib <ootiib@hot.ee> - 2022-12-06 21:38 -0800
                Re: An argument *against* (the liberal use of) references scott@slp53.sl.home (Scott Lurndal) - 2022-12-07 15:22 +0000
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-07 18:37 +0200
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-06 14:01 -0800
                Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-07 09:05 +0000
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-07 12:48 -0800
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-07 12:50 -0800
                Re: An argument *against* (the liberal use of) references Juha Nieminen <nospam@thanks.invalid> - 2022-12-08 07:52 +0000
                Re: An argument *against* (the liberal use of) references Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-08 05:50 -0800
                Re: An argument *against* (the liberal use of) references Michael S <already5chosen@yahoo.com> - 2022-12-08 13:30 -0800
                Re: An argument *against* (the liberal use of) references Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-09 12:50 -0800
                Re: An argument *against* (the liberal use of) references David Brown <david.brown@hesbynett.no> - 2022-12-11 12:18 +0100
                Re: An argument *against* (the liberal use of) references Paavo Helde <eesnimi@osa.pri.ee> - 2022-12-08 13:38 +0200
                Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-12-08 16:45 -0800
                Re: An argument *against* (the liberal use of) references Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-12-09 04:35 -0800
  Re: An argument *against* (the liberal use of) references Bonita Montero <Bonita.Montero@gmail.com> - 2022-11-22 15:36 +0100
  Re: An argument *against* (the liberal use of) references Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-11-22 15:21 +0000
  Re: An argument *against* (the liberal use of) references Richard Damon <Richard@Damon-Family.org> - 2022-11-22 10:48 -0500
    Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-11-22 13:18 -0800
  Re: An argument *against* (the liberal use of) references El Jo <giorgio.zoppi@gmail.com> - 2022-11-22 13:41 -0800
    Re: An argument *against* (the liberal use of) references "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-11-22 13:51 -0800
  Re: An argument *against* (the liberal use of) references Bonita Montero <Bonita.Montero@gmail.com> - 2022-11-23 20:08 +0100

csiph-web