bug#65908: 29.1.50; Emacs 29 regresses on macOS

[Zhang Haijun]

1. emacs -Q
2. paste the following code to scratch buffer and execute it for saveral times
   

(benchmark-progn

  (setq enable-dir-local-variables nil

            enable-local-variables nil)

  (let* ((test-dir "~/source/emacs-git/lisp")

             (file-list (directory-files test-dir t

                                                       "\\`[fsw].*[.]el\\'" t))

             (start-tm (current-time))

             end-tm buf buf-list)

      (dolist (test-file file-list)

        (setq buf (find-file-noselect test-file))

        (with-current-buffer buf

            (goto-char (point-min))

            (while (not (eobp))

              (end-of-defun)))

        (setq buf-list (cons buf buf-list)))

      (setq end-tm (current-time))

      (dolist (buf buf-list)

        (kill-buffer buf))

      (let ((delta (time-subtract end-tm start-tm)))

        (message "--- files: %d, delta: %s"

                     (length file-list) (float-time delta)))))

======== Result for Emacs 27: ======

--- files: 61, delta: 3.021547

Elapsed time: 3.030485s (0.173305s in 14 GCs)

"--- files: 61, delta: 3.021547"

--- files: 61, delta: 3.1373

Elapsed time: 3.145406s (0.181551s in 14 GCs)

"--- files: 61, delta: 3.1373"

--- files: 61, delta: 3.093033

Elapsed time: 3.100581s (0.162783s in 13 GCs)

"--- files: 61, delta: 3.093033"

======== Result for Emacs 29: =======

--- files: 61, delta: 5.271817

Elapsed time: 5.278284s (0.174266s in 13 GCs)

"--- files: 61, delta: 5.271817"

--- files: 61, delta: 4.919798

Elapsed time: 4.923492s (0.162042s in 13 GCs)

"--- files: 61, delta: 4.919798"

--- files: 61, delta: 5.127965

Elapsed time: 5.131604s (0.154718s in 12 GCs)

"--- files: 61, delta: 5.127965"

--- files: 61, delta: 4.978964

Elapsed time: 4.982757s (0.149401s in 12 GCs)

"--- files: 61, delta: 4.978964"

Time used in Emacs 29 is 1.6x than in Emacs 27. They are all built with "-O2".

I also tested on Linux. There is no such big regress.