setqとsetfの速度差

xyzzy

ついでに見つけた速度の差らしきものが面白かったのでメモ

(defun foo (count)
(let (qtime ftime i)
(dotimes (j 2)
(setq qtime (si:performance-counter))
(dotimes (k count) (setq i k))
(setq qtime (- (si:performance-counter) qtime)))
(dotimes (j 2)
(setq ftime (si:performance-counter))
(dotimes (k count) (setf i k))
(setq ftime (- (si:performance-counter) ftime)))
(format t "setq(count ~A): ~@10A (AVG: ~@5A)~%setf(count ~A): ~@10A (AVG: ~@5A)~%"
count qtime (truncate (/ qtime count))
count ftime (truncate (/ ftime count)))))

(foo 10000)
setq(count 10000): 270629 (AVG: 27)
setf(count 10000): 8047492 (AVG: 804)

(compile 'foo)
(foo 10000)
setq(count 10000): 5574 (AVG: 0)
setf(count 10000): 5501 (AVG: 0)

from http://pc7.2ch.net/test/read.cgi/software/1143621919/920