Opening org.el is slow

[nickdrozd]

Opening org.el is very slow for me.

I did some profiling, and it seems nameless is responsible.

(progn
  (profiler-start 'cpu)

  (dotimes (_ 5)
    (find-file "~/emacs/lisp/org/org.el"))

  (profiler-report)
  (profiler-stop))

Here are the relevants parts of the profile tree:

          - find-file                                           14269  89%
           - find-file-noselect                                 14253  89%
            - find-file-noselect-1                              14236  89%
             - after-find-file                                  14224  89%
              - normal-mode                                     14207  89%
               - set-auto-mode                                  14183  89%
                - set-auto-mode-0                               14183  89%
                 - emacs-lisp-mode                              14183  89%
                  - run-mode-hooks                              14178  89%
                   - apply                                       7101  44%
                    - run-hooks                                  7101  44%
                     - nameless-mode                             7101  44%
                      - nameless--after-hack-local-variables               7101  44%
                       - apply                                   4124  25%
                        - nameless--add-keywords                 4124  25%
                         - nameless--ensure                      4124  25%
                          + font-lock-fontify-region               4124  25%
                       - nameless--remove-keywords               2977  18%
                        - nameless--ensure                       2977  18%
                         + font-lock-fontify-region               2977  18%
                   - hack-local-variables                        7006  44%
                    - hack-local-variables-apply                 7006  44%
                     - run-hooks                                 7006  44%
                      - nameless--after-hack-local-variables               7006  44%
                       - apply                                   4102  25%
                        - nameless--add-keywords                 4102  25%
                         - nameless--ensure                      4102  25%
                          + font-lock-fontify-region               4102  25%
                       - nameless--remove-keywords               2904  18%
                        - nameless--ensure                       2904  18%
                         + font-lock-fontify-region               2904  18%

It looks like nameless--after-hack-local-variables is getting called twice, and so ultimately font-lock-fontify-region (which is the expensive part) is getting called twice too.

Is it actually necessary for that to get called twice? I don't understand how hooks or local variables work.

[nickdrozd]

GNU Emacs 26.1.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30) of 2018-06-25

emacs-lisp-mode-hook => (nameless-mode)

[Malabarba]

Nameless uses font-locking to do its thing. Looks like the problem is that org.el is a very big file and it takes a while to font-lock completely.

I think the solution here would be for nameless to font-lock more lazily (I believe font-lock already supports that, so we're probably just using it wrong).