Performance and Evaluation of Lisp Systems - Dreamsongs

§ 3.13 Division by 2 187
As is apparent from the metering, these benchmarks simply CONS, take CAR
and CDR, and do some function calling or GO’ing.
These benchmarks were proposed by a computer scientist at Bell Laborato-
ries. He thought that they best epitomized what his programs did—function-calls,
CONS, CAR, CDR, and iteration. He wanted to find out how Franz Lisp on a
Vax 11/780 did vis-à-vis other implementations. He was surprised to find out
that the iterative version ran slower than the recursive one on the Vax 11/780.
After some investigation, we found out that the iterative version had a number
of sequential MOVL instructions in a row—more than the recursive version. At
that time (1982), the Vax 11/780 did very poorly on MOVL’s, and by counting
cycle times we were able to justify the results we saw. Since then, the problem
has been corrected on Vaxes and possibly in Franz itself.
Meter for Iterative Div2
Cdr’s 240000
Null’s 121200
Cons’s 120200
Car’s 120000
ITERATIVE-DIV2 1200
=’s 201
1−’s 200
CREATE-N 1
Total 603002
3.13.3 Translation Notes
The INTERLISP versions are straightforward:
Meter for Recursive Div2
Cdr’s 240000
Null’s 121200
RECURSIVE-DIV2 121200
Cons’s 120200
Car’s 120000
1−’s 200
=’s 201
CREATE-N 1
Total 723002
(DEFINEQ
(DIV2
(LAMBDA (l)
(for L A on l by (CDDR L) do (push A (CAR L))
finally (RETURN A))))
(DV2
(LAMBDA (l)
(if (NULL l)
then NIL
else (CONS (CAR l)
(DV2 (CDDR l)))))))