Performance of m-v-l

gistfile1.lisp

(defun mvb (f)
  (declare (optimize (speed 3) (safety 1) (debug 1)))
  (multiple-value-bind (x y) (funcall f)
    (values (+ x y) (- x y))))

(defun mvl (f)
  (declare (optimize (speed 3) (safety 1) (debug 1)))
  (let* ((l (multiple-value-list (funcall f)))
         (x (car l))
         (y (cadr l)))
    (declare (dynamic-extent l)
             (type list l))
    (values (+ x y) (- x y))))

(flet ((f ()
         (values (random 100) (random 100))))
  (time (iter (repeat 10000000)
              (sum (multiple-value-bind (x y) (mvb #'f)
                     (+ x y)))))
  (time (iter (repeat 10000000)
              (sum (multiple-value-bind (x y) (mvl #'f)
                     (+ x y))))))

; (ITER (REPEAT 10000000) (SUM (MULTIPLE-VALUE-BIND (X Y) (MVB #'F) (+ X Y)))) took 1,570,168 microseconds (1.570168 seconds) to run 
;                     with 2 available CPU cores.
; During that period, 1,508,985 microseconds (1.508985 seconds) were spent in user mode
;                     1,360 microseconds (0.001360 seconds) were spent in system mode
; (ITER (REPEAT 10000000) (SUM (MULTIPLE-VALUE-BIND (X Y) (MVL #'F) (+ X Y)))) took 1,663,267 microseconds (1.663267 seconds) to run 
;                     with 2 available CPU cores.
; During that period, 1,605,071 microseconds (1.605071 seconds) were spent in user mode
;                     2,342 microseconds (0.002342 seconds) were spent in system mode