🚀 go-pugleaf

  To: comp.lang.clos@cis.ohio-state.edu
  Date: 20 Sep 92 14:18:02 GMT
  Organization: School of Mathematics, University of Bath, UK
  From: C D Burdorf <mascdb@gdr.bath.ac.uk>
  Sender: commonloops-request@cis.ohio-state.edu
  References: <9209181825.AA08510@thelonius.mitre.org>.edu
  Subject: Re: Built-in functions (was Re: Beginner's Question - CLOS)
  
  In article <9209181825.AA08510@thelonius.mitre.org> john@linus.mitre.org writes:
  >
  >True, but many (most?) of the "built-in" functions in a Lisp
  >implementation are neither implemented in assembly language, nor are
  >they usually open-coded into calling code. 
  
  I'm suprised people are arguing with me on this point.  I C coded
  the exponential distribution function and did a foreign function
  interface to CMU Lisp and it was many times faster than what the
  CMU common lisp compiler could produce with declares and speed at 3
  and safety at 0.  
  
  I've seen over and over again cases where people can write
  assembly code that is faster than what Lisp compilers produce.
  
  HCL is a very fast (on sun3's) lisp and part of the reason is
  that much of it is written in assembly language.

To avoid comparing apples to oranges, it might be helpful to get examples
of code from people who have been commenting about performance of C and
Lisp.  Often when someone rewrites software, it has different performance
characteristics the second time.  For example, porting to a parallel
processor can make your code faster even on a uniprocessor, if you spend
more time worrying about performance than you did when your first wrote
your algorithm.

I can imagine that simply proclaiming speed 3 and saftey 0 may not help
performance much unless you do other things too.  For example, if your Lisp
conses floats, or your algorithm uses trig functions that require crossing
the Lisp/C boundary a lot.

I can imaging that there must be things that are equally fast in C,
assembly, or Lisp.  For example, a properly declared (AREF X 3) is still
only 1 instruction in all these languages.