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Re: 'smttter IBMdroids

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On 9/2/2011 10:10 AM, Robert Myers wrote:

> There are probably many possible taxonomies for computing, but the one
> that drives my dislike of IBM having any significant influence over
> technical supercomputing is that there are
>
> a. Calculations where you know days, and maybe even weeks, months, or
> years ahead of time what will transpire when you run the program.
>
> b. Operations where what the computer does next is entirely at the
> whim of forces completely beyond its control and almost always beyond
> anyone's ability even to predict such that the system will *always*
> even run reliably.
>
> Most technical computing is category a and all but small slices of
> business computing are category b.  More and more business computing
> that might at one time have fit into category a is gradually sliding
> into category b, as business analytics are increasingly done in real
> time.
>
> Category b has an awful lot of painful constraints, and my hat is off
> to anyone who can work successfully with those kinds of requirements.
> Satisfying those requirements must require an awful lot of brain,
> money, and attention-share, and I would strongly prefer to think that
> most computers for technical computing were built by people who were
> only vaguely aware of category b and certainly did not spend most of
> the work week in that mindset.
>
> Itanium was a processor that was clearly built with a category a
> mindset.  That's why itanium got so much of my attention and maybe
> part of why it failed--that, plus the fact that most of the people who
> laid hands on Itanium were by habit category b users.  How much easier
> it would be, it seemed to me, to build a really fast category a
> processor and/or computer because, in most cases, you *do* know the
> future.
>
> By the time you get down to microarchitecture as it is currently
> practiced, the whole world starts to look like category b.  Itanium
> was a toe in the water of a microarchitecture designed more for
> category a, and I've taken up a lot of time and space here asking what
> went wrong because that's the kind of processing that interests me.
> A computer built almost entirely for category a would have serious
> issues dealing with remaining category b needs that it couldn't avoid
> dealing with, but, in my never-sufficiently-humble opinion, if we ever
> build a supercomputer for technical computing that isn't a sour joke,
> it will be because all the category b constraints were left behind.
> That's why I want IBM out of the business.


Interesting.   How do you characterize your category a versus category b?

Real-time?  Server type workloads?  Pointer chasing over linked data 
structures?

I agree that Itanium's targeting of server workloads was odd.

I disagree that "microarchitecture as it is currently practiced" favors 
category b.  If category b is characterized as I said above.

 From my point of view, the last 10-15 years of microarchitecture have 
been characterized by overemphasizing category a stuff --- witness the 
landslide of SIMD packed vector instructions. GPU SIMD style 
architectures.  The  overemphasis on sequential access pattern bandwidth.

And my understanding is that you have not been terribly happy with that.

I think that your categorization needs to be tweaked:

Category a
     a.1 sequential and local
     a.2 non-sequential and non-local

Category b
     Not knowing your definition, I'll suppose  it to be RT, server, 
pointer chasing.

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'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-08-31 22:15 -0400
  Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-08-31 22:20 -0400
    Re: 'smttter IBMdroids Anne & Lynn Wheeler <lynn@garlic.com> - 2011-08-31 22:31 -0400
      Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-01 07:30 -0700
  Re: 'smttter IBMdroids Quadibloc <jsavard@ecn.ab.ca> - 2011-09-01 09:48 -0700
    Re: 'smttter IBMdroids nmm1@cam.ac.uk - 2011-09-01 17:58 +0100
    Re: 'smttter IBMdroids Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-09-01 10:58 -0700
      Re: 'smttter IBMdroids nmm1@cam.ac.uk - 2011-09-01 18:51 +0100
    Re: 'smttter IBMdroids Anne & Lynn Wheeler <lynn@garlic.com> - 2011-09-01 15:42 -0400
    Re: 'smttter IBMdroids Robert Wessel <robertwessel2@yahoo.com> - 2011-09-01 18:19 -0500
      Re: 'smttter IBMdroids Anne & Lynn Wheeler <lynn@garlic.com> - 2011-09-01 20:57 -0400
      Re: 'smttter IBMdroids nmm1@cam.ac.uk - 2011-09-02 09:17 +0100
      Re: 'smttter IBMdroids nmm1@cam.ac.uk - 2011-09-02 09:19 +0100
        Re: 'smttter IBMdroids Robert Wessel <robertwessel2@yahoo.com> - 2011-09-02 04:44 -0500
          Re: 'smttter IBMdroids nmm1@cam.ac.uk - 2011-09-02 11:39 +0100
            Re: 'smttter IBMdroids Robert Wessel <robertwessel2@yahoo.com> - 2011-09-02 11:14 -0500
        Re: 'smttter IBMdroids Robert Wessel <robertwessel2@yahoo.com> - 2011-09-02 04:47 -0500
          Re: 'smttter IBMdroids nmm1@cam.ac.uk - 2011-09-02 11:26 +0100
          Re: 'smttter IBMdroids Anne & Lynn Wheeler <lynn@garlic.com> - 2011-09-02 08:48 -0400
          Re: 'smttter IBMdroids Anne & Lynn Wheeler <lynn@garlic.com> - 2011-09-02 09:29 -0400
  Re: 'smttter IBMdroids Del Cecchi <delcecchi@gmail.com> - 2011-09-01 17:15 -0500
    Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-02 10:10 -0700
      Re: innovation from Armonk, was 'smttter IBMdroids John Levine <johnl@iecc.com> - 2011-09-02 21:21 +0000
        Re: innovation from Armonk, was 'smttter IBMdroids nmm1@cam.ac.uk - 2011-09-02 21:56 +0100
        Re: innovation from Armonk, was 'smttter IBMdroids Anne & Lynn Wheeler <lynn@garlic.com> - 2011-09-02 17:49 -0400
      Re: 'smttter IBMdroids Del Cecchi <delcecchi@gmail.com> - 2011-09-02 18:04 -0500
        Re: 'smttter IBMdroids Thomas Womack <twomack@chiark.greenend.org.uk> - 2011-09-03 00:16 +0100
          Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-03 14:25 -0400
            Re: 'smttter IBMdroids Thomas Womack <twomack@chiark.greenend.org.uk> - 2011-09-03 20:09 +0100
        Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-03 22:02 -0400
          Re: 'smttter IBMdroids Del Cecchi <delcecchi@gmail.com> - 2011-09-03 21:50 -0500
            Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-03 23:52 -0400
      Re: 'smttter IBMdroids "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-05 08:26 -0700
        Re: 'smttter IBMdroids Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-09-05 11:14 -0700
          Re: 'smttter IBMdroids Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-09-05 22:05 +0200
          Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-05 17:27 -0400
        Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-05 17:16 -0400
          Re: 'smttter IBMdroids "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-09-05 14:40 -0700
            Re: 'smttter IBMdroids Robert Myers <rbmyersusa@gmail.com> - 2011-09-05 15:45 -0700
        Re: 'smttter IBMdroids Del Cecchi <delcecchi@gmail.com> - 2011-09-06 21:47 -0500

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