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
? 

? (y-or-n-p "Well, what's it going to be?") Well, what's it going to be? (y or n) y

Error: Two UNREAD-CHARs without intervening READ-CHAR on #<SELECTION-INPUT-STREAM :UTF-8 (TTY/6) #x30004193150D> While executing: CCL::%IOBLOCK-UNTYI, in process Listener(94). Type :POP to abort, :R for a list of available restarts. Type :? for other options.

1 >

It would be nice to have an editor command that shows callers of the symbol you are pointing it. Note that runtime support is already implemented (there is a function ccl::callers), so this is just a matter of providng UI for it.