Re: Green Compiler ?

From	George Neuner <gneuner2@comcast.net>
Newsgroups	comp.compilers
Subject	Re: Green Compiler ?
Date	2012-12-31 01:24 -0500
Organization	A noiseless patient Spider
Message-ID	<13-01-002@comp.compilers> (permalink)
References	(1 earlier) <12-12-012@comp.compilers> <12-12-022@comp.compilers> <12-12-028@comp.compilers> <12-12-034@comp.compilers> <12-12-037@comp.compilers>

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On Sun, 30 Dec 2012 08:14:26 +0100, Hans-Peter Diettrich
<DrDiettrich1@aol.com> wrote:

>Peter Dassow schrieb:
>> On 28.12.2012 08:35, Hans-Peter Diettrich wrote:
>>>
>>> Please note that most CMOS processor power consumption results from
>>> switching (stray) capacities, and only a small percentage for leak
>>> currents. E.g. a register or gate consumes such power whenever a bit is
>>> changed, and almost nothing when it has reached an stable state.

Smaller transistors have more leakage.

>> So using extensively registers instead of "conventional" memory (e.g.
>> DDR-RAM, memory outside a CPU) will save energy (if equal functionality
>> is given) ?
>
>I don't see a relationship here, except that external memory is slow
>and [in x86] a couple of caches and address translations are involved
>in reading from RAM.

But associative cache and external memory accesses both are power
intensive.

>But registers are a very scarce resource, so that frequent loading from
>memory is hardly avoidable.

My opinions are colored by experience with DSPs, but I have long
thought that it would be helpful to have a few K-words of non-cache
scratchpad memory very close (1..2 cycles) to the CPU.

George

Thread

Green Compiler ? Abid <abidmuslim@gmail.com> - 2012-12-20 02:00 -0800
  Re: Green Compiler ? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-23 08:18 +0000
    Re: Green Compiler ? Peter Dassow <z80eu@arcor.de> - 2012-12-26 19:31 +0100
      Re: Green Compiler ? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-28 03:09 +0000
      Re: Green Compiler ? Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2012-12-28 08:35 +0100
        Re: Green Compiler ? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-28 16:14 +0000
        Re: Green Compiler ? Peter Dassow <z80eu@arcor.de> - 2012-12-29 09:35 +0100
          Re: Green Compiler ? Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2012-12-30 08:14 +0100
            Re: Green Compiler ? George Neuner <gneuner2@comcast.net> - 2012-12-31 01:24 -0500
              Re: Green Compiler ? "Jonathan Thornburg" <jthorn@astro.indiana.edu> - 2013-01-02 04:09 +0000
                Re: Green Compiler ? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-01-02 18:29 +0000
              Re: Green Compiler ? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-01-02 05:11 +0000
              Re: Green Compiler ? Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2013-01-02 07:29 +0100
                Re: Green Compiler ? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-01-02 19:52 +0000
                Re: Green Compiler ? "Charles Richmond" <numerist@aquaporin4.com> - 2013-01-04 08:59 -0600
  Re: Green Compiler ? "Nils M Holm" <nmh@t3x.org> - 2012-12-23 10:01 +0100
    Re: Green Compiler ? Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2012-12-24 05:16 +0100
    Re: Green Compiler ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-12-27 13:36 +0000
      Re: Green Compiler ? "Nils M Holm" <nmh@t3x.org> - 2012-12-28 09:11 +0100
        Re: Green Compiler ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-12-28 16:57 +0000
        Re: Green Compiler ? George Neuner <gneuner2@comcast.net> - 2012-12-28 12:57 -0500
          Re: Green Compiler ? "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-12-30 09:22 +0100
    Re: Green Compiler ? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-12-27 21:59 -0600
  Re: Green Compiler ? Walter Banks <walter@bytecraft.com> - 2012-12-28 10:42 -0500

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