Re: "C Is The Greenest Programming Language" by: Chris Lott

From	Manfred <noname@add.invalid>
Newsgroups	comp.lang.c, comp.lang.c++
Subject	Re: "C Is The Greenest Programming Language" by: Chris Lott
Date	2021-11-23 20:59 +0100
Organization	Aioe.org NNTP Server
Message-ID	<snjh78$8k0$1@gioia.aioe.org> (permalink)
References	<snh51g$c1q$1@dont-email.me> <snivri$15p1$1@gioia.aioe.org> <snj2k7$vojf$1@news.xmission.com> <snj65u$tmi$1@dont-email.me>

Cross-posted to 2 groups.

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On 11/23/2021 5:51 PM, David Brown wrote:
> On 23/11/2021 16:50, Kenny McCormack wrote:
>> In article <snivri$15p1$1@gioia.aioe.org>, Manfred  <noname@add.invalid> wrote:
>>> On 11/22/2021 11:19 PM, Lynn McGuire wrote:
>>>> Our results show interesting find- ings, such as, slower/faster
>>>> languages consuming less/more energy, and how memory usage influences
>>>> energy consump- tion
>>>
>>> I find the correlation slower/faster language respectively less/more
>>> energy quite confusing. In fact I believe it is the opposite.
>>
>> Yes.  I think this was misstated/sloppily-written in the original text.
>>
>> It depends, of course, on what exactly you mean by a "slower" language.
>> It is true that if you run the CPU at a slower speed (and that would make
>> for a slower processing model), then you will use less energy.
>>
> 
> It is /not/ true that running the CPU at a slower speed uses less energy
> - at least, it is often not true.  It is complicated.
> 
> There are many aspects that affect how much energy is taken for a given
> calculation.
> 
> Regarding programming languages, it is fairly obvious that a compiled
> language that takes fewer instructions to do a task using optimised
> assembly is going to use less energy than a language that has less
> optimisation and more assembly instructions, or does some kind of
> interpretation.  Thus C (and other optimised compiled languages like
> C++, Rust or Ada) are going to come out top.
> 
> It is less obvious how the details matter.  Optimisation flags have an
> effect, as do choices of instruction (as functional blocks such as SIMD
> units or floating point units) may be dynamically enabled.  For some
> target processors, unrolling a loop to avoid branches will reduce energy
> consumption - on others, rolled loops to avoid cache misses will be
> better.  Some compilers targeting embedded systems (where power usage is
> often more important) have "optimise for power" as a third option to the
> traditional "optimise for speed" and "optimise for size".
> 
> The power consumption for a processor is the sum of the static power and
> the dynamic power.  Dynamic power is proportional to the frequency and
> the square of the voltage.  And energy usage is power times time.
> 
> A processor that is designed to run at high frequency is likely to have
> high-leakage transistors, and therefore high static power - when the
> circuits are enabled.  But the faster you get the work done, the higher
> a proportion of the time you can have in low-power modes with minimal
> static power.  On the other hand, higher frequencies may need higher
> voltages.
> 
> As a rule of thumb, it is better to run your cpu at its highest
> frequency - or at the highest it can do without raising the voltage -
> and get the calculation done fast.  Then you can spend more time in
> low-power sleep modes.  However, entering and exiting sleep modes takes
> time and energy, so you don't want to do it too often - hence the
> "big-little" processor combinations where you have a slower core that
> can be switched on and off more efficiently.
> 

I am not sure about that "rule" - in general modern integrated 
electronics waste most energy during state transitions, and that is 
directly coupled with clock frequency, but I admit there may be more to 
it that I don't know.

One consideration about the balance between clock speed and efficiency 
is that it is totally relative to how old the technology is. I am pretty 
confident that an old Pentium is much less efficient than a modern i7 
(just to consider popular PC stuf only), even if the latter runs faster 
than the former.
The reason is not just because of the added value of the environmental 
footprint in today's public opinion; the fact is that heat dissipation 
is a major bottleneck in IC technology, so in order for a modern 
processor to perform according to nowadays' standards and not melt after 
a few minutes of operation, it /has/ to be built with efficient technology.
But then comes "modern" programming, with all its fuzz of managed code, 
JIT gibber, thousands of DLL dependencies, etc., not to forget "modern" 
OS's that eat Tflops just to perform even the simplest of tasks, and 
there goes all of that efficiency.

Thread

"C Is The Greenest Programming Language" by: Chris Lott Lynn McGuire <lynnmcguire5@gmail.com> - 2021-11-22 16:19 -0600
  Re: "C Is The Greenest Programming Language" by: Chris Lott "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-22 14:58 -0800
    Re: "C Is The Greenest Programming Language" by: Chris Lott Juha Nieminen <nospam@thanks.invalid> - 2021-11-23 07:10 +0000
      Re: "C Is The Greenest Programming Language" by: Chris Lott "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-23 13:12 -0800
        Re: "C Is The Greenest Programming Language" by: Chris Lott Juha Nieminen <nospam@thanks.invalid> - 2021-11-24 10:54 +0000
          Re: "C Is The Greenest Programming Language" by: Chris Lott Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 12:01 +0100
            Re: "C Is The Greenest Programming Language" by: Chris Lott David Brown <david.brown@hesbynett.no> - 2021-11-24 13:58 +0100
      Re: "C Is The Greenest Programming Language" by: Chris Lott "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-23 13:23 -0800
  Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-22 18:25 -0500
    Re: "C Is The Greenest Programming Language" by: Chris Lott Juha Nieminen <nospam@thanks.invalid> - 2021-11-23 07:21 +0000
      Re: "C Is The Greenest Programming Language" by: Chris Lott Thiago Adams <thiago.adams@gmail.com> - 2021-11-23 04:50 -0800
      Re: "C Is The Greenest Programming Language" by: Chris Lott Guillaume <message@bottle.org> - 2021-11-23 17:56 +0100
        Re: "C Is The Greenest Programming Language" by: Chris Lott Juha Nieminen <nospam@thanks.invalid> - 2021-11-24 10:55 +0000
      Re: "C Is The Greenest Programming Language" by: Chris Lott Lynn McGuire <lynnmcguire5@gmail.com> - 2021-11-23 19:00 -0600
        Re: "C Is The Greenest Programming Language" by: Chris Lott scott@slp53.sl.home (Scott Lurndal) - 2021-11-24 16:04 +0000
    Re: "C Is The Greenest Programming Language" by: Chris Lott Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 11:43 +0100
  Re: "C Is The Greenest Programming Language" by: Chris Lott om@iki.fi (Otto J. Makela) - 2021-11-23 14:17 +0200
    Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-23 16:53 +0000
      Re: "C Is The Greenest Programming Language" by: Chris Lott om@iki.fi (Otto J. Makela) - 2021-11-24 11:40 +0200
        Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-24 15:49 +0000
    Re: "C Is The Greenest Programming Language" by: Chris Lott Lynn McGuire <lynnmcguire5@gmail.com> - 2021-11-23 19:01 -0600
      Re: "C Is The Greenest Programming Language" by: Chris Lott om@iki.fi (Otto J. Makela) - 2021-11-24 11:33 +0200
        Re: "C Is The Greenest Programming Language" by: Chris Lott Lynn McGuire <lynnmcguire5@gmail.com> - 2021-11-24 15:28 -0600
  Re: "C Is The Greenest Programming Language" by: Chris Lott Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-23 14:39 +0100
    Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-23 16:55 +0000
      Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-23 12:28 -0500
        Re: "C Is The Greenest Programming Language" by: Chris Lott Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-23 19:05 +0100
          Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-23 13:41 -0500
            Re: "C Is The Greenest Programming Language" by: Chris Lott Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-23 19:53 +0100
              Re: "C Is The Greenest Programming Language" by: Chris Lott Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-11-23 16:31 -0800
              Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-23 21:27 -0500
                Re: "C Is The Greenest Programming Language" by: Chris Lott Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-24 18:32 +0100
                Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-24 12:54 -0500
                Re: "C Is The Greenest Programming Language" by: Chris Lott Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-24 20:52 +0100
                Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-24 15:13 -0500
                Re: "C Is The Greenest Programming Language" by: Chris Lott Bonita Montero <Bonita.Montero@gmail.com> - 2021-11-25 19:13 +0100
          Re: "C Is The Greenest Programming Language" by: Chris Lott Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-11-23 16:25 -0800
        Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-24 15:48 +0000
          Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-24 11:54 -0500
            Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-25 11:19 +0000
              Re: "C Is The Greenest Programming Language" by: Chris Lott Juha Nieminen <nospam@thanks.invalid> - 2021-11-25 11:46 +0000
                Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-25 15:57 +0000
              Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-25 07:04 -0500
                Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-25 15:59 +0000
                Re: "C Is The Greenest Programming Language" by: Chris Lott Thiago Adams <thiago.adams@gmail.com> - 2021-11-26 03:37 -0800
  Re: "C Is The Greenest Programming Language" by: Chris Lott Manfred <noname@add.invalid> - 2021-11-23 16:03 +0100
    Re: "C Is The Greenest Programming Language" by: Chris Lott gazelle@shell.xmission.com (Kenny McCormack) - 2021-11-23 15:50 +0000
      Re: "C Is The Greenest Programming Language" by: Chris Lott David Brown <david.brown@hesbynett.no> - 2021-11-23 17:51 +0100
        Re: "C Is The Greenest Programming Language" by: Chris Lott DozingDog@thekennel.co - 2021-11-23 17:00 +0000
          Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-23 12:36 -0500
          Re: "C Is The Greenest Programming Language" by: Chris Lott David Brown <david.brown@hesbynett.no> - 2021-11-23 19:24 +0100
            Re: "C Is The Greenest Programming Language" by: Chris Lott Richard Damon <Richard@Damon-Family.org> - 2021-11-23 13:50 -0500
              Re: "C Is The Greenest Programming Language" by: Chris Lott David Brown <david.brown@hesbynett.no> - 2021-11-23 20:02 +0100
        Re: "C Is The Greenest Programming Language" by: Chris Lott Manfred <noname@add.invalid> - 2021-11-23 20:59 +0100
          Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-11-23 20:50 +0000
            Re: "C Is The Greenest Programming Language" by: Chris Lott Ian Collins <ian-news@hotmail.com> - 2021-11-24 11:18 +1300
              Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-11-23 22:58 +0000
            Re: "C Is The Greenest Programming Language" by: Chris Lott David Brown <david.brown@hesbynett.no> - 2021-11-23 23:46 +0100
              Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-11-24 13:59 +0000
                Re: "C Is The Greenest Programming Language" by: Chris Lott antispam@math.uni.wroc.pl - 2021-12-11 13:25 +0000
                Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-12-11 14:54 +0000
            Re: "C Is The Greenest Programming Language" by: Chris Lott Manfred <noname@add.invalid> - 2021-11-25 12:12 +0100
          Re: "C Is The Greenest Programming Language" by: Chris Lott David Brown <david.brown@hesbynett.no> - 2021-11-23 23:35 +0100
            Re: "C Is The Greenest Programming Language" by: Chris Lott Manfred <noname@add.invalid> - 2021-11-24 15:30 +0100
              Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-11-24 14:43 +0000
      Re: "C Is The Greenest Programming Language" by: Chris Lott Manfred <noname@add.invalid> - 2021-11-23 20:29 +0100
    Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-11-23 16:14 +0000
    Re: "C Is The Greenest Programming Language" by: Chris Lott Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 11:56 +0100
      Re: "C Is The Greenest Programming Language" by: Chris Lott Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-24 10:14 -0800
        Re: "C Is The Greenest Programming Language" by: Chris Lott David Brown <david.brown@hesbynett.no> - 2021-11-24 19:55 +0100
          Re: "C Is The Greenest Programming Language" by: Chris Lott Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 21:13 +0100
        Re: "C Is The Greenest Programming Language" by: Chris Lott Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 21:11 +0100
      Re: "C Is The Greenest Programming Language" by: Chris Lott Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 21:17 +0100
        Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-11-24 20:42 +0000
          Re: "C Is The Greenest Programming Language" by: Chris Lott Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 23:25 +0100
          Re: "C Is The Greenest Programming Language" by: Chris Lott antispam@math.uni.wroc.pl - 2021-12-11 14:07 +0000
            Re: "C Is The Greenest Programming Language" by: Chris Lott Bart <bc@freeuk.com> - 2021-12-11 18:46 +0000
              [OT] Lisp.  Was: "C Is The Greenest Programming Language" by: Chris Lott Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-11 20:11 +0000
                Re: "C Is The Greenest Programming Language" Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-13 17:59 -0800
                Re: "C Is The Greenest Programming Language" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-14 03:18 +0000
                Re: "C Is The Greenest Programming Language" Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-16 10:57 -0800
                Re: "C Is The Greenest Programming Language" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-16 22:03 +0000
                Re: "C Is The Greenest Programming Language" Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-20 02:40 -0800
                Re: "C Is The Greenest Programming Language" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-20 12:05 +0000
  Re: "C Is The Greenest Programming Language" by: Chris Lott "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-11-24 14:12 -0800
    Re: "C Is The Greenest Programming Language" by: Chris Lott Manfred <noname@add.invalid> - 2021-11-25 12:00 +0100
  Re: "C Is The Greenest Programming Language" by: Chris Lott Paavo Helde <eesnimi@osa.pri.ee> - 2021-12-05 22:51 +0200
    Re: "C Is The Greenest Programming Language" by: Chris Lott "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-05 19:20 -0800
      Re: "C Is The Greenest Programming Language" by: Chris Lott Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-06 01:52 -0800
        Re: "C Is The Greenest Programming Language" by: Chris Lott "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-06 12:19 -0800
          Re: "C Is The Greenest Programming Language" by: Chris Lott "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-06 12:27 -0800
    Re: "C Is The Greenest Programming Language" by: Chris Lott Manfred <noname@add.invalid> - 2021-12-06 12:28 +0100
      Re: "C Is The Greenest Programming Language" by: Chris Lott Paavo Helde <eesnimi@osa.pri.ee> - 2021-12-06 13:40 +0200
    Re: "C Is The Greenest Programming Language" by: Chris Lott Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-06 16:21 +0100

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