bug#62780: 30.0.50; Redisplay gets slow when using Org tables + show-trailing-whitespace

[Ihor Radchenko <yantar92@posteo.net>]

Eli Zaretskii <eliz@gnu.org> writes:

> See above: show-trailing-whitespace is not the main culprit here;
> these particular display properties are.  If you could produce a perf
> profile with this recipe, it might give ideas for speeding up the C
> code without any changes on the Lisp level.

Here are perf results when typing, using the same recipe.

Full summary:

    29.89%  emacs         emacs                       [.] lookup_char_property
    16.58%  emacs         emacs                       [.] next_interval
    13.99%  emacs         emacs                       [.] Fassq
     5.44%  emacs         emacs                       [.] find_interval
     5.17%  emacs         emacs                       [.] Fcdr
     3.97%  emacs         emacs                       [.] Fnext_single_property_change
     2.32%  emacs         emacs                       [.] composition_compute_stop_pos
     1.51%  emacs         emacs                       [.] validate_interval_range
     1.03%  emacs         emacs                       [.] get_char_property_and_overlay
     0.99%  emacs         emacs                       [.] textget
     0.79%  emacs         emacs                       [.] plist_get
     0.77%  emacs         emacs                       [.] produce_stretch_glyph
     0.76%  emacs         emacs                       [.] balance_an_interval
     0.54%  emacs         emacs                       [.] lface_hash

Call graph:

(next_interval is spread thin across the call graph, used all over the place)

99.10%--command_loop_1
 97.65%--read_key_sequence
  97.55%--read_char
   97.51%--redisplay redisplay_internal
    97.49%--redisplay_windows internal_condition_case_1 redisplay_window_0
     97.49%--redisplay_window
      |65.03%--try_window
      ||32.55%--display_line
      || 28.90%--get_next_display_element
      ||  28.83%--next_element_from_buffer
      ||   28.75%--handle_stop
      ||    23.87%--compute_stop_pos
      ||     23.52%--composition_compute_stop_pos
      ||      21.61%--find_composition
      ||       21.31%--Fnext_single_property_change
      ||        17.84%--textget
      ||         16.84%--lookup_char_property
      ||	  6.15%--builtin_lisp_symbol
      ||	   5.28%--make_lisp_symbol
      ||	  5.94%--Fassq
      || 32.47%--partial_line_height move_it_to
      |   31.11%--move_it_in_display_line_to
      |    28.95%--get_next_display_element
      |    28.86%--next_element_from_buffer
      |     28.80%--handle_stop
      |      ... 16.75%--lookup_char_property
      |32.42%--set_vertical_scroll_bar
        32.41%--move_it_to
	 31.05%--move_it_in_display_line_to
	  28.86%--get_next_display_element
	   ... 16.54%--lookup_char_property


-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>