Custom Query (1030 matches)

A colleague noticed that the following function can run more slowly with a suitable type declaration. I've reproduced his results on Linux:

Welcome to Clozure Common Lisp Version 1.12-dev-r16729M-trunk (LinuxX8664)!

Here are the commands:

(declaim (OPTIMIZE (COMPILATION-SPEED 0) (DEBUG 0) (SPEED 3) (SPACE 0) (SAFETY 0)))
(defun fibonacci (n)
  (declare (type (integer 0 *) n))
  (if (= n 0)
      0
    (if (= n 1)
        1
      (+ (fibonacci (- n 1)) (fibonacci (- n 2))))))

Then:

? (time (fibonacci 38))
(FIBONACCI 38)
took 912,371 microseconds (0.912371 seconds) to run.
During that period, and with 8 available CPU cores,
     912,812 microseconds (0.912812 seconds) were spent in user mode
         804 microseconds (0.000804 seconds) were spent in system mode
 1 minor page faults, 0 major page faults, 0 swaps.
39088169
? 

But here we see the time cut in more than half when we remove the type declaration:

? (time (fibonacci 38))
(FIBONACCI 38)
took 383,980 microseconds (0.383980 seconds) to run.
During that period, and with 8 available CPU cores,
     382,068 microseconds (0.382068 seconds) were spent in user mode
       2,433 microseconds (0.002433 seconds) were spent in system mode
 1 minor page faults, 0 major page faults, 0 swaps.
39088169
? 

On my machine workpersistence.lisp writes a Hemlock editor window to the workpersistence.text file even when I have closed that window. The attached file contains a couple extra lines of code that seem to fix that.

Let me know if there is a better venue for patching.

From Eric Marsden on openmcl-devel:

| Welcome to Clozure Common Lisp Version 1.7-dev-r14686M  (LinuxX8664)!
| ? (defun foo ()
|     (catch 'ct5 (throw 'ct5 (logior -920833 (the integer
-2513842743151)))))
| FOO
| ? (foo)
| > Error: Can't throw to tag -263425
| > While executing: FOO, in process listener(1).
`----