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Re: Green Compiler ?

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On 23.12.2012 09:18, glen herrmannsfeldt wrote:
> Abid <abidmuslim@gmail.com> wrote:
>
>> It seems that the Power Wall is becoming a major  issue, especially for High
>> Performance Computing. Current compilers work has two dimensional model, i.e.,
>> all the optimization phases are targeted either towards reducing execution
>> time or code size. My question is: Do we need to change this model and make it
>> three dimensional by adding power axis in the search space? If yes, then we
>> have to revisit all the phases and adjust them or come up with  new cost
>> models for these phases.
>
> It should be energy, not power. You can always reduce the power by
> doing the calculation slower. Energy is power times time (more
> generally, the integral of E(t)dt).

Efficiency is NOT equal to power consumption.  You can do calculations
(e.g. divide something) in more than one way, means by using the
"fastest" operations, or by using the "best" algorithm, means using
the most efficient opcodes (that is NOT using the fastest operations,
e.g. shifting/rotating bits), e.g. using a DIVIDE opcode instead which
can probably cost more clock cycles.  That does not mean just to make
it slow, you should still choose the most efficient way (means doing
something with fewer opcodes, regardless of how many clock cycles are
used for per opcode).  But I'm not sure this kind of optimization
would save a significant percentage compared to an clock cycle
optimized binary.

Regards
  Peter

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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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