Performance measurements (was: python on the smalltalk VM)

[Cameron Laird]

In article <lcd7a9rldg.fsf at gaffa.mit.edu>,
Douglas Alan  <nessus at mit.edu> wrote:
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>I'm just quoting Guido from a while back.  This is, of course, for
>doing number crunching using only bare Python and normal loops.  If
>you use NumPy or PyAPL or some other highly optimized C-coded
>extension to do matrix operations on large matrices, then you can of
>course do as well as C, because your number crunching is really being
>done by C.  This is assuming you can figure out a way to turn your
>number crunching problem into operations on large matrices.
>
>All this should come as no shock -- 100 times slower for an
>interpreted language is just par for a good interpreter.  Before the
>spiffy Self compiler, state of the art was 10x slower than C for a
>really bitchin' highly optimized Smalltalk compiler.
>
>|>oug

Help me, Mr. Alan.  I remember a time when "100 times
slower for an interpreted language [was] just par for
a good interpreter."  I have a lot of trouble repro-
ducing that today.  If it'll help, I can pull some of
my '80s era hosts and interpreters from the closet. 
Yes, I get a factor of between 100 and 300 for empty
loops, but, as soon as they do anything useful, the
multiple drops down to a range more like ten--definitely
not a hundred.

What I remember Guido saying is something like, "Maybe
Python is only one one-hundredth as fast on do-nothing
loops; I can live with that, that is, I have more im-
portant things to spend my time on" (that's heavily
paraphrased).

I'll summarize:  I don't understand what point is
being made when someone says, "Interpreters are 1% as
fast as compilers", and the evidence all has to do with
empty loops.  It makes me think I'm missing something.
If you mollify the claim to 10% as fast, I ... well, in
that case, I can at least believe we're looking at the
same data.

Again, I recognize the Lisp community has a long and
interesting history with performance comparisons.  I'm
not reflecting on that at all.  I'm talking about cur-
rent Python and, let's say, gcc--I take those to be
consistent with your intent.
-- 

Cameron Laird <claird at NeoSoft.com>
Business:  http://www.Phaseit.net
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