Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!aioe.org!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail
From: Julian Fondren <ayrnieu@gmail.com>
Newsgroups: comp.lang.forth
Subject: Re: Forth Performance Question
Date: Sun, 07 Aug 2011 01:01:11 -0500
Organization: A noiseless patient Spider
Lines: 62
Message-ID: <86r54x4v6g.fsf@gmail.com>
References: <f0fc528e-2fdb-42af-a66d-976ebfa73b88@c8g2000prn.googlegroups.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: mx04.eternal-september.org; posting-host="cO8zBIpB9LiP7q+vFZIJrA"; logging-data="10807"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18a/xbcX7uXyfyOX/TRPOZpG2quGP3legA="
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (windows-nt)
Cancel-Lock: sha1:6sFOclXOgku0UvcLCzmvmYX+0tE= sha1:TIkLpjmQ+clBZVZ1RHsFWehKBfQ=
Xref: x330-a1.tempe.blueboxinc.net comp.lang.forth:4630

TS <thinksquared@gmail.com> writes:

> Hi,

(This guy's posting from Google Groups, a web interface for Usenet run
by a company that's too inept even to announce to their own users that
their service is having problems.  I already sent him an email to warn
him to look for replies in other venues.)

> I'm just starting to learn Forth, and trying to assess the performance
> differences between some of the common free Forths. I ran this
> program:

> : foo  1 1000000 * drop ;
> : test 1 100000000 ?DO foo LOOP ;
>
> On BigForth 2.4.0 it took ~22 sec to run, Retro v11 (with "times"
> syntax, compiled with -O3), took ~23 sec and GForth 0.7.0 ~65 sec to
> run.

bigForth et al actually do the work at run-time, because you told them
to.  Java may have noticed that the entire program is a no-op.  GCC
certainly can:

  $ cat opt.c
  int main (void) { int i; for (i = 0; i < 999999; i++); return 0; }
  $ gcc -O3 -S opt.c
  $ cat opt.s
          .file   "opt.c"
          .section        .text.startup,"ax",@progbits
          .p2align 4,,15
          .globl  main
          .type   main, @function
  main:
  .LFB0:
          .cfi_startproc
          xorl    %eax, %eax
          ret
          .cfi_endproc
  .LFE0:
          .size   main, .-main
          .ident  "GCC: (GNU) 4.6.0 20110603 (Red Hat 4.6.0-10)"
          .section        .note.GNU-stack,"",@progbits

That's it.  See any loops in that?

If your programs need to do a lot of work that can be done at
compile-time, or that reduce to nothing, of the two languages, only
Forth lets you do this explicitly, and very naturally; you don't have
to hope that an optimizer will notice.

> a) Since BigForth is compiles to native code, why is its performance
> similar to Retro, which is interpreted?

Your _benchmark_ doesn't highlight any differences.  A benchmark that
gave native code more to do, might do better.  A real program should do
better.

Although, I'm not equipped even to agree that Retro is interpreted.
It's one of those defiantly non-ANS Forth-reminiscent languages.

http://en.wikipedia.org/wiki/Software_rot#Example