Re: Green Compiler ?

From	"Jonathan Thornburg" <jthorn@astro.indiana.edu>
Newsgroups	comp.compilers
Subject	Re: Green Compiler ?
Date	2013-01-02 04:09 +0000
Organization	Compilers Central
Message-ID	<13-01-003@comp.compilers> (permalink)
References	(2 earlier) <12-12-022@comp.compilers> <12-12-028@comp.compilers> <12-12-034@comp.compilers> <12-12-037@comp.compilers> <13-01-002@comp.compilers>

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George Neuner <gneuner2@comcast.net> wrote:
>>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.

The Cray-2 and Cray-3 had this (I think they called it "local memory").
Alas, compilers had a lot of trouble making good use of it.  As John
McCalpin put it in 1998 (at the time he was at SGI):

# Local memories work fine if an experience performance person gets
# to rewrite the code.  It gets a lot more difficult if you have
# to educate a compiler to do the right thing....

I don't know if compilers have improved significantly in this area.

And on the hardware side, you'd have to figure out what to do on
context switch...
--
-- "Jonathan Thornburg [remove -animal to reply]" <jthorn@astro.indiana-zebra.edu>
   Dept of Astronomy, Indiana University, Bloomington, Indiana, USA
   "C++ is to programming as sex is to reproduction. Better ways might
    technically exist but they're not nearly as much fun." -- Nikolai Irgens
[It sounds like if we keep working, we might reinvent register windows. -John]

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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