[Python-Dev] Dictionary sparseness

[Alex Martelli]

On Monday 05 May 2003 07:11 pm, Jeremy Hylton wrote:
   ...
> Have you seen the work on gray-box systems?
>
> http://www.cs.wisc.edu/graybox/
>
> The philosophy of this project seems to be "You can observe an awful lot
> just by watching."  (Apologies to Yogi.)  The approach is to learn how a
> particular service is implemented, e.g. what buffer-replacement
> algorithm is used, by observing its behavior.  Then write an application
> that exploits that knowledge to drive the system into optimized behavior
> for  the application.  No madvise() necessary.

Haven't read that URL, but this seems to summarize the way we had
to work with Fortran compilers on 3090-VF's back in the late '80s -- no
way to explicitly advise the compiler about what and how to vectorize,
so, lots of experimentation and tweaking to find how what the (expletive
deleted) heuristics the GD beast was using, and how to outsmart it
and get it to vectorize what *WE* wanted rather than what *IT* thought
was good for us.

What fun!  And of course we got to redo it all over again when a new
compiler release came out.

No thanks.  I've paid my dues and I hope I will *NEVER* again have to
work with a system that thinks it's so smart it doesn't need my advisory
input -- or at least not on anything that's as performance-crucial as
those Fortran programs were (most of my work in IBM Research in
did with Rexx -- that's when I learned to love scripting! -- but then and
again we did have to crunch really huge batches of numbers).


Alex