Optimization for directory-files about f.el

[alphapapa]

@rejeep I rediscovered this in my notes, came here to repost it, and found that I already had. :) Here's another benchmark using bench-multi:

(defun f--collect-entries--tb (path recursive)
  (with-temp-buffer
    (let (result
          (entries
           (-reject
            (lambda (file)
              (or
               (equal (f-filename file) ".")
               (equal (f-filename file) "..")))
            (directory-files path t))))
      (cond (recursive
             (-map
              (lambda (entry)
                (if (f-file? entry)
                    (setq result (cons entry result))
                  (when (f-directory? entry)
                    (setq result (cons entry result))
                    (setq result (append result (f--collect-entries entry recursive))))))
              entries))
            (t (setq result entries)))
      result)))

#+BEGIN_SRC el
  (bench-multi :times 100
    :ensure-equal t
    :forms (("without temp buffer" (f--collect-entries "~/.emacs.d" nil))
            ("with temp buffer" (f--collect-entries--tb "~/.emacs.d" nil))))
#+END_SRC

Form	x faster than next	Total runtime	# of GCs	Total GC runtime
with temp buffer	1.66	0.087498083	0	0.0
without temp buffer	slowest	0.14550272800000003	0	0.0

[Phundrak]

Hi, I can’t reproduce these results, in fact using a temporary buffer makes the function slower. This is what I get when I execute the code you shared in your first comment:

without temp buffer	0.031098385	0	0.0
with temp buffer	0.033553346	0	0.0

Can you still reproduce your results?

[alphapapa]

Can you still reproduce your results?

I don't know, that was nearly four years ago, and Emacs has had a few releases since then. What version did you test on? Were you using emacs -q?

[Phundrak]

I am currently on Emacs 28.1 and on master. The results I shared above are from master, below are the results I get on Emacs 28.1 on an Intel Celeron N2840 (2.16GHz max): without temp buffer 0.104090848 0 0.0 with temp buffer 0.11387473000000001 0 0.0 I guess this hack used to be useful but that is no longer the case.

…

-- Lucien “Phundrak” Cartier-Tilet <https://phundrak.com> (Français) <https://phundrak.com/en> (English) Sent from GNU/Emacs