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


Groups > comp.lang.c++ > #91263 > unrolled thread

Sieve of Eratosthenes

Started byBonita Montero <Bonita.Montero@gmail.com>
First post2023-08-16 15:37 +0200
Last post2023-08-30 19:02 +0200
Articles 20 on this page of 146 — 13 participants

Back to article view | Back to comp.lang.c++


Contents

  Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-16 15:37 +0200
    Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-16 10:57 -0700
      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-16 20:21 +0200
        Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-16 12:17 -0700
      Re: Sieve of Eratosthenes Paavo Helde <eesnimi@osa.pri.ee> - 2023-08-16 21:44 +0300
        Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-16 12:09 -0700
    Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:17 +0200
      Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:21 +0200
      Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:39 +0200
        Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-16 23:59 +0200
          Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-16 16:27 -0700
      Re: Sieve of Eratosthenes red floyd <no.spam.here@its.invalid> - 2023-08-16 18:06 -0700
        Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-16 19:26 -0700
          Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-27 12:26 -0700
            Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-28 00:49 +0100
              Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-27 23:23 -0700
                Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-28 15:53 +0200
                  Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-28 09:03 -0700
                    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-28 18:47 +0200
                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-30 13:01 +0200
                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-30 15:38 +0000
                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-30 18:31 +0200
                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 08:22 +0000
                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 11:00 +0200
                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:23 +0000
                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:28 +0200
                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 11:52 +0200
                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:22 +0000
                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:32 +0200
                                    Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:44 +0000
                                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:50 +0200
                                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 10:26 +0000
                                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 12:59 +0200
                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 12:30 +0000
                                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 15:33 +0200
                                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 13:49 +0000
                                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 15:59 +0200
                                                    Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 14:03 +0000
                                                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 16:15 +0200
                                                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 14:39 +0000
                                                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 16:59 +0200
                                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 15:01 +0000
                                                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 17:05 +0200
                                                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-09-01 15:08 +0000
                                                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 17:15 +0200
                                Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-31 21:33 +0100
                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-09-01 05:35 +0200
                              Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-31 14:43 +0000
                                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 16:57 +0200
                                  Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-31 16:10 +0000
                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-31 15:25 +0000
                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-31 17:33 +0200
                                    Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-31 16:12 +0000
                  Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-28 23:08 +0100
              Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-28 15:15 -0700
                Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-28 23:41 +0100
                  Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-30 17:45 -0700
                    Re: Sieve of Eratosthenes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-08-31 03:18 +0100
            Re: Sieve of Eratosthenes Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-08-28 15:08 -0700
        Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 08:42 +0200
          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 11:38 +0200
            Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-17 12:50 +0200
              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 13:10 +0200
              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-17 17:47 +0200
              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-21 11:00 +0200
                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-21 17:19 +0000
                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-21 19:50 +0200
                    Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-21 18:12 +0000
                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-21 20:22 +0200
                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-21 19:01 +0000
                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 05:27 +0200
                            Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-21 23:25 -0700
                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:23 +0200
                                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:59 +0200
                                Re: Sieve of Eratosthenes Öö Tiib <ootiib@hot.ee> - 2023-08-22 05:15 -0700
                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 14:23 +0200
                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 06:56 +0000
                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:27 +0200
                                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 11:34 +0200
                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 14:13 +0000
                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 16:17 +0200
                                    Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 14:27 +0000
                                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 16:48 +0200
                                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 14:57 +0000
                                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 17:00 +0200
                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 17:56 +0000
                                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 20:13 +0200
                                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 18:18 +0000
                                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-22 20:50 +0200
                                                    Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 06:51 +0000
                                                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 09:59 +0200
                                                        Re: Sieve of Eratosthenes Richard Damon <Richard@Damon-Family.org> - 2023-08-23 07:52 -0400
                                                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 14:40 +0200
                                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:24 +0000
                                                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:30 +0200
                                                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:36 +0000
                                                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:38 +0200
                                                                    Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:43 +0000
                                                                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:45 +0200
                                                                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 17:49 +0000
                                                                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:05 +0200
                                                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:18 +0000
                                                                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:20 +0200
                                                                          Re: Sieve of Eratosthenes Daniel <danielaparker@gmail.com> - 2023-08-23 11:13 -0700
                                                                            Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:17 +0200
                                                                              Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-23 11:20 -0700
                                                                                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:24 +0200
                                                                                  Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:25 +0000
                                                                                    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:29 +0200
                                                                                      Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:40 +0000
                                                                                        Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:49 +0200
                                                                                          Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-25 16:07 +0000
                                                                                            Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-25 18:10 +0200
                                                                                              Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-25 16:15 +0000
                                                                                                Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-25 18:18 +0200
                                                                                                  Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-26 08:03 +0000
                                                                                                    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-26 10:16 +0200
                                                                                                      Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-26 08:27 +0000
                                                                                Re: Sieve of Eratosthenes Daniel <danielaparker@gmail.com> - 2023-08-23 11:37 -0700
                                                                                  Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-26 15:33 -0700
                                                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:20 +0000
                                                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:32 +0200
                                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 14:41 +0000
                                                              Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 16:47 +0200
                                                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 17:51 +0000
                                                                  Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-23 20:09 +0200
                                                                    Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-23 18:51 +0000
                                                                      Re: Sieve of Eratosthenes "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2023-08-24 11:25 -0700
                                                                    Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:22 +0000
                                                                      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:27 +0200
                                                                        Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-24 17:37 +0000
                                                                          Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-24 19:52 +0200
                                                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-25 16:07 +0000
                                                          Re: Sieve of Eratosthenes Daniel <danielaparker@gmail.com> - 2023-08-23 08:00 -0700
                                          Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-22 15:49 +0000
                                            Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-22 17:58 +0000
                                              Re: Sieve of Eratosthenes scott@slp53.sl.home (Scott Lurndal) - 2023-08-22 18:24 +0000
                                                Re: Sieve of Eratosthenes Muttley@dastardlyhq.com - 2023-08-23 06:50 +0000
      Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-17 13:43 -0700
        Re: Sieve of Eratosthenes "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2023-08-18 02:00 +0200
          Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-18 05:01 -0700
            Re: Sieve of Eratosthenes wij <wyniijj5@gmail.com> - 2023-08-18 17:02 -0700
    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-28 06:15 +0200
    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-28 09:43 +0200
    Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-29 20:34 +0200
      Re: Sieve of Eratosthenes Bonita Montero <Bonita.Montero@gmail.com> - 2023-08-30 19:02 +0200

Page 5 of 8 — ← Prev page 1 2 3 4 [5] 6 7 8  Next page →


#91344

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-22 16:17 +0200
Message-ID<uc2g1f$2eh5h$1@dont-email.me>
In reply to#91343
Am 22.08.2023 um 16:13 schrieb Muttley@dastardlyhq.com:

> No, not in most cases as endless bloated frameworks ...

I'm using standard C++ and no bloating framworks. The memory-con-
sumtion is eight times less than with your code because I store
each bool as a bit. Your code has bloat, not mine in that sense.

> There's a big difference between code thats fully featured and code
> thats needlessly compicated because the developer(s) were unable to
> think clearly or see the obvious solution.

It overburdens you, not every developer.

[toc] | [prev] | [next] | [standalone]


#91345

FromMuttley@dastardlyhq.com
Date2023-08-22 14:27 +0000
Message-ID<uc2gjn$2ekj3$1@dont-email.me>
In reply to#91344
On Tue, 22 Aug 2023 16:17:21 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 22.08.2023 um 16:13 schrieb Muttley@dastardlyhq.com:
>
>> No, not in most cases as endless bloated frameworks ...
>
>I'm using standard C++ and no bloating framworks. The memory-con-
>sumtion is eight times less than with your code because I store
>each bool as a bit. Your code has bloat, not mine in that sense.

Accessing bits in a word is normally slower than accessing the whole word
on most CPUs. However due to the huge memory this sort of algo can use this
access time is probably more than offset by paging delays.

Using bits doesn't make you a genius.

>> There's a big difference between code thats fully featured and code
>> thats needlessly compicated because the developer(s) were unable to
>> think clearly or see the obvious solution.
>
>It overburdens you, not every developer.

Whoosh...

[toc] | [prev] | [next] | [standalone]


#91346

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-22 16:48 +0200
Message-ID<uc2hsd$2eqis$1@dont-email.me>
In reply to#91345
Am 22.08.2023 um 16:27 schrieb Muttley@dastardlyhq.com:

> Accessing bits in a word is normally slower than accessing the whole word
> on most CPUs. ...

I have shown that when the amount of data is large enough, access time
has the greatest weight. Furthermore, most of the calculations for the
bits within the byte in other arithmetic units take place in parallel.
If I choose the data set small enough, your algorithm is faster, but
then performance doesn't count anyway.

> Using bits doesn't make you a genius.

Did I claim that for myself ?

[toc] | [prev] | [next] | [standalone]


#91347

FromMuttley@dastardlyhq.com
Date2023-08-22 14:57 +0000
Message-ID<uc2ico$2eu3a$1@dont-email.me>
In reply to#91346
On Tue, 22 Aug 2023 16:48:45 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 22.08.2023 um 16:27 schrieb Muttley@dastardlyhq.com:
>
>> Accessing bits in a word is normally slower than accessing the whole word
>> on most CPUs. ...
>
>I have shown that when the amount of data is large enough, access time
>has the greatest weight. Furthermore, most of the calculations for the
>bits within the byte in other arithmetic units take place in parallel.

CPUs only have 1 data bus no matter how many cores they have so the optimum
number of threads for this sort of algorithm is very much a suck it and
see approach depending on hardware and on a single core CPU your approach
would suck badly.

>> Using bits doesn't make you a genius.
>
>Did I claim that for myself ?

By denigrating anyone who doesn't like your coding style the implication is
there for all to see. You think yourself a better programmer than anyone
else on this group.

[toc] | [prev] | [next] | [standalone]


#91348

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-22 17:00 +0200
Message-ID<uc2iiq$2eu9j$1@dont-email.me>
In reply to#91347
Am 22.08.2023 um 16:57 schrieb Muttley@dastardlyhq.com:

> CPUs only have 1 data bus no matter how many cores they have so the optimum
> number of threads for this sort of algorithm is very much a suck it and
> see approach depending on hardware and on a single core CPU your approach
> would suck badly.

Data is fetched in quantities of a cacheline size. And with my code
an eight of that quantity is fetched from memory. That's the reason
while my code is much faster than yours.

> By denigrating anyone who doesn't like your coding style the implication
> is there for all to see. You think yourself a better programmer than anyone
> else on this group.

That's obvious. I'm programming C++ since 1992 and I program at all
since I'm 10.

[toc] | [prev] | [next] | [standalone]


#91350

FromMuttley@dastardlyhq.com
Date2023-08-22 17:56 +0000
Message-ID<uc2ss5$2grks$1@dont-email.me>
In reply to#91348
On Tue, 22 Aug 2023 17:00:42 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 22.08.2023 um 16:57 schrieb Muttley@dastardlyhq.com:
>
>> CPUs only have 1 data bus no matter how many cores they have so the optimum
>> number of threads for this sort of algorithm is very much a suck it and
>> see approach depending on hardware and on a single core CPU your approach
>> would suck badly.
>
>Data is fetched in quantities of a cacheline size. And with my code

If it has to be paged from disk in the first place the size of the cache is a 
total irrelevance as far as time taken is concerned.

>an eight of that quantity is fetched from memory. That's the reason
>while my code is much faster than yours.

As I said, it depends on the hardware. Try both on a Z80 and see what happens.

>> By denigrating anyone who doesn't like your coding style the implication
>> is there for all to see. You think yourself a better programmer than anyone
>> else on this group.
>
>That's obvious.

Thanks for proving you're as arrogant as I thought.

>I'm programming C++ since 1992 and I program at all
>since I'm 10.

If you want to get into a pissing contest about who's been programming longer
I suspect a lot of people on this group have been doing it a lot longer than
you.

[toc] | [prev] | [next] | [standalone]


#91352

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-22 20:13 +0200
Message-ID<uc2tru$2h0an$1@dont-email.me>
In reply to#91350
Am 22.08.2023 um 19:56 schrieb Muttley@dastardlyhq.com:

> If it has to be paged from disk in the first place the size of the
> cache is a total irrelevance as far as time taken is concerned.

No one uses software that actually pages to disk.
Paging is just for that the softwar doesn't crash.

> As I said, it depends on the hardware. Try both on a Z80 and see what happens.

Your code wasn't intended for a Z-80.

> Thanks for proving you're as arrogant as I thought.

When you're good in sth. you often appear arrogant.

> If you want to get into a pissing contest about who's been programming
> longer I suspect a lot of people on this group have been doing it a lot
> longer than you.

Maybe, but at this level.

[toc] | [prev] | [next] | [standalone]


#91353

FromMuttley@dastardlyhq.com
Date2023-08-22 18:18 +0000
Message-ID<uc2u4r$2h243$1@dont-email.me>
In reply to#91352
On Tue, 22 Aug 2023 20:13:17 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 22.08.2023 um 19:56 schrieb Muttley@dastardlyhq.com:
>
>> If it has to be paged from disk in the first place the size of the
>> cache is a total irrelevance as far as time taken is concerned.
>
>No one uses software that actually pages to disk.
>Paging is just for that the softwar doesn't crash.

I suggest you go and google how operating system virtual memory works.

>> As I said, it depends on the hardware. Try both on a Z80 and see what
>happens.
>
>Your code wasn't intended for a Z-80.

What was it intended for then given it was written in basic C?

>> Thanks for proving you're as arrogant as I thought.
>
>When you're good in sth. you often appear arrogant.

"sth"?

>> If you want to get into a pissing contest about who's been programming
>> longer I suspect a lot of people on this group have been doing it a lot
>> longer than you.
>
>Maybe, but at this level.

At your level? Absolutely.

[toc] | [prev] | [next] | [standalone]


#91355

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-22 20:50 +0200
Message-ID<uc302f$2hahp$1@dont-email.me>
In reply to#91353
Am 22.08.2023 um 20:18 schrieb Muttley@dastardlyhq.com:
> On Tue, 22 Aug 2023 20:13:17 +0200
> Bonita Montero <Bonita.Montero@gmail.com> wrote:
>> Am 22.08.2023 um 19:56 schrieb Muttley@dastardlyhq.com:
>>
>>> If it has to be paged from disk in the first place the size of the
>>> cache is a total irrelevance as far as time taken is concerned.
>>
>> No one uses software that actually pages to disk.
>> Paging is just for that the softwar doesn't crash.
> 
> I suggest you go and google how operating system virtual memory works.

Swapping is for stability and not for performance.
No one considers running applications actually swapping.

> What was it intended for then given it was written in basic C?

You didn't write that on a Z-80.

[toc] | [prev] | [next] | [standalone]


#91357

FromMuttley@dastardlyhq.com
Date2023-08-23 06:51 +0000
Message-ID<uc4a9v$2qq8f$1@dont-email.me>
In reply to#91355
On Tue, 22 Aug 2023 20:50:55 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 22.08.2023 um 20:18 schrieb Muttley@dastardlyhq.com:
>> On Tue, 22 Aug 2023 20:13:17 +0200
>> Bonita Montero <Bonita.Montero@gmail.com> wrote:
>>> Am 22.08.2023 um 19:56 schrieb Muttley@dastardlyhq.com:
>>>
>>>> If it has to be paged from disk in the first place the size of the
>>>> cache is a total irrelevance as far as time taken is concerned.
>>>
>>> No one uses software that actually pages to disk.
>>> Paging is just for that the softwar doesn't crash.
>> 
>> I suggest you go and google how operating system virtual memory works.
>
>Swapping is for stability and not for performance.

For stability? Seriously?

>No one considers running applications actually swapping.
>
>> What was it intended for then given it was written in basic C?
>
>You didn't write that on a Z-80.

No, but I've got a Z80 C compiler that would happily compile and run it.

[toc] | [prev] | [next] | [standalone]


#91358

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-23 09:59 +0200
Message-ID<uc4e92$2rd5a$1@dont-email.me>
In reply to#91357
Am 23.08.2023 um 08:51 schrieb Muttley@dastardlyhq.com:
> On Tue, 22 Aug 2023 20:50:55 +0200
> Bonita Montero <Bonita.Montero@gmail.com> wrote:
>> Am 22.08.2023 um 20:18 schrieb Muttley@dastardlyhq.com:
>>> On Tue, 22 Aug 2023 20:13:17 +0200
>>> Bonita Montero <Bonita.Montero@gmail.com> wrote:
>>>> Am 22.08.2023 um 19:56 schrieb Muttley@dastardlyhq.com:
>>>>
>>>>> If it has to be paged from disk in the first place the size of the
>>>>> cache is a total irrelevance as far as time taken is concerned.
>>>>
>>>> No one uses software that actually pages to disk.
>>>> Paging is just for that the softwar doesn't crash.
>>>
>>> I suggest you go and google how operating system virtual memory works.
>>
>> Swapping is for stability and not for performance.
> 
> For stability? Seriously?

Main memory has a latency from 20 - 30ns per access. My 1TB Samsung
PCIe 4.0 SSD has a synchronous latency of 32us, that's up to factor
1.800. Do you really think that a swappable application is usable ?
Swapping is just for low memory conditions so that the application
won't stop or crash.

> No, but I've got a Z80 C compiler that would happily compile and run it.

I don't believe you. And no one is using Z-80s today.

[toc] | [prev] | [next] | [standalone]


#91359

FromRichard Damon <Richard@Damon-Family.org>
Date2023-08-23 07:52 -0400
Message-ID<1qmFM.783950$TPw2.627247@fx17.iad>
In reply to#91358
On 8/23/23 3:59 AM, Bonita Montero wrote:
> 
> Main memory has a latency from 20 - 30ns per access. My 1TB Samsung
> PCIe 4.0 SSD has a synchronous latency of 32us, that's up to factor
> 1.800. Do you really think that a swappable application is usable ?
> Swapping is just for low memory conditions so that the application
> won't stop or crash.

Your forgetting that in thst 32us you get a whole sector of data, not 
just one word, so the slow down in much less of a factor.

Also, and application being "slow" is better than the application just 
can't be run because it uses too much resource (even having the machine 
all to itself).

Yes, with todays 64-bit address space, we tend to not need to design in 
"swapping" as might have been needed with 16-bit machines, but many 
applications are still designed based on the knowledge that they are 
likely using more memory that is likely physically present, so they try 
to optimize access to take that into account.

Good practice looks at the whole hierarchy, after all, data in Level 1 
cache is MUCH faster to access then data in main memory, which is faster 
than data on local storage, is much faster than data out on the network.

Forget that and you task suddenly hits a wall and just crawls.

[toc] | [prev] | [next] | [standalone]


#91360

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-23 14:40 +0200
Message-ID<uc4uo3$2tv6l$1@dont-email.me>
In reply to#91359
Am 23.08.2023 um 13:52 schrieb Richard Damon:

> Your forgetting that in thst 32us you get a whole sector of data,
> not  just one word, so the slow down in much less of a factor.

I'm not forgetting that. I dropped this because the relationship is
that hughe anyway. The sector is the size of a cacheline and when you
switch on your computer the SDRAM's burst size is configured according
to the cacheline size.

> Also, and application being "slow" is better than the application just 
> can't be run because it uses too much resource (even having the machine 
> all to itself).

That's what I told: swapping is just a stability feature. Applications
are normally not useable when they swap or even the whole machine isn't
usable because essential pages of other processes were swapped out.

> Yes, with todays 64-bit address space, we tend to not need to design
> in  "swapping" as might have been needed with 16-bit machines, ...

Swapspace makes sense even if the swap actually isn't touched. When you
commit some memory with VirtualAlloc() under Windows and memory hasn't
been touched yet the kernel has subtracted an according amount of space
from swap so that if swapping would be necessary when the pages are
touched the first time there's enough swap space.
Solaris works the same way. But Linux by default does overcommit so that
an application might crash if there's not enough swapspace if a page is
touched the first time. But Linux can be configured like Windows and
Solaris so that there's enough swap reserved when you allocate memory.
The problem with that under Linux is that if you have a massively for-
king application where the child processes modify only a small portion
of the shared memory there might be a large amount of memory subtracted
from swap.

> ... but many  applications are still designed based on the knowledge
> that they are  likely using more memory that is likely physically present, 
> ...

That's not really an optimizatiob but a common assumption.

[toc] | [prev] | [next] | [standalone]


#91362

FromMuttley@dastardlyhq.com
Date2023-08-23 14:24 +0000
Message-ID<uc54qh$2v1bp$1@dont-email.me>
In reply to#91360
On Wed, 23 Aug 2023 14:40:36 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 23.08.2023 um 13:52 schrieb Richard Damon:
>> Yes, with todays 64-bit address space, we tend to not need to design
>> in  "swapping" as might have been needed with 16-bit machines, ...
>
>Swapspace makes sense even if the swap actually isn't touched. When you
>commit some memory with VirtualAlloc() under Windows and memory hasn't

Does windows still use a filesystem file for swap making it horrendously
slow as swap data has to go in and out via the high level filesystem layer
or has MS discovered the concept of swap partitions yet?

>The problem with that under Linux is that if you have a massively for-
>king application where the child processes modify only a small portion
>of the shared memory there might be a large amount of memory subtracted
>from swap.
>
>> ... but many  applications are still designed based on the knowledge
>> that they are  likely using more memory that is likely physically present, 
>> ...
>
>That's not really an optimizatiob but a common assumption.

Sadly not in the Java world where "grab as much memory as you can on 
startup" seems to be the JVM motto.

[toc] | [prev] | [next] | [standalone]


#91363

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-23 16:30 +0200
Message-ID<uc5559$2v27t$1@dont-email.me>
In reply to#91362
Am 23.08.2023 um 16:24 schrieb Muttley@dastardlyhq.com:

> Does windows still use a filesystem file for swap making it horrendously
> slow as swap data has to go in and out via the high level filesystem layer
> or has MS discovered the concept of swap partitions yet?

That's not slow if you simply memorize the cluster-addresses of the
blocks holding the pagefile in non-pageable memory. That's that simple
that I think it's the way how ms does that.

> Sadly not in the Java world where "grab as much memory as you can on
> startup" seems to be the JVM motto.

That's not true. Java-applications would be even less responsive
since a garbage collection involves copying the whole heap to a
new heap.

[toc] | [prev] | [next] | [standalone]


#91365

FromMuttley@dastardlyhq.com
Date2023-08-23 14:36 +0000
Message-ID<uc55h8$2v57p$1@dont-email.me>
In reply to#91363
On Wed, 23 Aug 2023 16:30:01 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 23.08.2023 um 16:24 schrieb Muttley@dastardlyhq.com:
>> Sadly not in the Java world where "grab as much memory as you can on
>> startup" seems to be the JVM motto.
>
>That's not true. Java-applications would be even less responsive
>since a garbage collection involves copying the whole heap to a
>new heap.

Certainly seemed to be the case back when I was involved in Java. One would
hope its evolved since then.

[toc] | [prev] | [next] | [standalone]


#91366

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-23 16:38 +0200
Message-ID<uc55lr$2v5is$1@dont-email.me>
In reply to#91365
Am 23.08.2023 um 16:36 schrieb Muttley@dastardlyhq.com:
> On Wed, 23 Aug 2023 16:30:01 +0200
> Bonita Montero <Bonita.Montero@gmail.com> wrote:
>> Am 23.08.2023 um 16:24 schrieb Muttley@dastardlyhq.com:
>>> Sadly not in the Java world where "grab as much memory as you can on
>>> startup" seems to be the JVM motto.
>>
>> That's not true. Java-applications would be even less responsive
>> since a garbage collection involves copying the whole heap to a
>> new heap.
> 
> Certainly seemed to be the case back when I was involved in Java. One would
> hope its evolved since then.
> 

Others just have the composure to devote
themselves to complex problems, you don't.

[toc] | [prev] | [next] | [standalone]


#91368

FromMuttley@dastardlyhq.com
Date2023-08-23 14:43 +0000
Message-ID<uc55uo$2v7k7$1@dont-email.me>
In reply to#91366
On Wed, 23 Aug 2023 16:38:51 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 23.08.2023 um 16:36 schrieb Muttley@dastardlyhq.com:
>> On Wed, 23 Aug 2023 16:30:01 +0200
>> Bonita Montero <Bonita.Montero@gmail.com> wrote:
>>> Am 23.08.2023 um 16:24 schrieb Muttley@dastardlyhq.com:
>>>> Sadly not in the Java world where "grab as much memory as you can on
>>>> startup" seems to be the JVM motto.
>>>
>>> That's not true. Java-applications would be even less responsive
>>> since a garbage collection involves copying the whole heap to a
>>> new heap.
>> 
>> Certainly seemed to be the case back when I was involved in Java. One would
>> hope its evolved since then.
>> 
>
>Others just have the composure to devote
>themselves to complex problems, you don't.

It wasn't my problem other than the JVM was killing our servers performance
so go swivel on it.

[toc] | [prev] | [next] | [standalone]


#91369

FromBonita Montero <Bonita.Montero@gmail.com>
Date2023-08-23 16:45 +0200
Message-ID<uc561h$2v7nu$1@dont-email.me>
In reply to#91368
Am 23.08.2023 um 16:43 schrieb Muttley@dastardlyhq.com:

> On Wed, 23 Aug 2023 16:38:51 +0200
> Bonita Montero <Bonita.Montero@gmail.com> wrote:

>> Others just have the composure to devote
>> themselves to complex problems, you don't.

> It wasn't my problem other than the JVM was killing our
> servers performance so go swivel on it.

Java Frameworks are really complex and you're at the level of
simple details. So I think you never were involved in such projects.

[toc] | [prev] | [next] | [standalone]


#91373

FromMuttley@dastardlyhq.com
Date2023-08-23 17:49 +0000
Message-ID<uc5gqi$317jq$1@dont-email.me>
In reply to#91369
On Wed, 23 Aug 2023 16:45:06 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:
>Am 23.08.2023 um 16:43 schrieb Muttley@dastardlyhq.com:
>
>> On Wed, 23 Aug 2023 16:38:51 +0200
>> Bonita Montero <Bonita.Montero@gmail.com> wrote:
>
>>> Others just have the composure to devote
>>> themselves to complex problems, you don't.
>
>> It wasn't my problem other than the JVM was killing our
>> servers performance so go swivel on it.
>
>Java Frameworks are really complex and you're at the level of
>simple details. So I think you never were involved in such projects.

You must be a very insecure person constantly putting others down to make
yourself feel better.

What job do you do? Do you even have one?

[toc] | [prev] | [next] | [standalone]


Page 5 of 8 — ← Prev page 1 2 3 4 [5] 6 7 8  Next page →

Back to top | Article view | comp.lang.c++


csiph-web