When I press [M-q] on the following org-mode buffer content:

* 绵羊是太阳能农场的优秀管理员
:PROPERTIES:
:SOURCE: 奇客Solidot–传递最新科技情报
:DATE(original): [2021-10-25 Mon 17:28]
:DATE: [2021-10-26 Tue]
:END:

有利于放养家畜和有利于太阳能发电的地方经常重叠。它们都需要平坦、阳光充足,没有高大植被的开阔地。因此
太阳能生产商正越来越多地租用农田运营。

太阳能产量的增加具有环境效益,但是其代价可能是农业产量的下降。因而人们越来越有兴趣寻找在同一个地方结
合农业和太阳能生产的方法。对于康奈尔大学农业综合企业副教授 Todd Schmit 来说,[问题的答案是羊群]()。

这仍然是一个新领域,部分农民正和太阳能生产商合作,在后者的土地上放牧。太阳能生产商付钱给农民,让他们
把羊送到他们的太阳能农场,羊会吃掉杂草和其他可能阻挡阳光到达太阳能板的植物。

羊得到了食物,农民得到了报酬,而太阳能生产商则在不使用割草机和除草机的情况下管理农场的植被------割草
机和除草机很难伸到太阳能面板下方,而且需要使用化石燃料。American Solar Grazing Association(ASGA)的
[报告]()显示,该行业自 2017 年以来,一直在纽约州扩张。帝国州(纽约州)报告指出,目前有 900 英亩的太阳能
生产土地正在放牧。增长空间仍然很大。

Emacs often suspend for a long time.

So I take a profiling test with Emacs profiler. Seems org-fill-element spend a lot of CPU and memory.

Here is the result:

CPU Profiler Report:

3623  65% - command-execute
3623  65%  - call-interactively
3623  65%   - funcall-interactively
3141  56%    - org-fill-paragraph
3141  56%     - let
3141  56%      - cond
3141  56%       - let
3141  56%        - unwind-protect
3141  56%         - progn
3140  56%          - while
2096  37%           - org-fill-element
2090  37%            - let
2090  37%             - unwind-protect
2089  37%              - progn
2079  37%               - let
2044  36%                - save-excursion
2032  36%                 - org-element-at-point
2027  36%                  - let
1546  27%                   - if
1473  26%                    - progn
1473  26%                     - if
1473  26%                      - if
1467  26%                       - org-element--cache-sync
1467  26%                        - if
1467  26%                         - progn
1441  25%                          - save-current-buffer
1416  25%                           - if
1410  25%                            - let
1400  25%                             - let
1334  23%                              - catch
1332  23%                               - and
1332  23%                                - org-indent-add-properties
1332  23%                                 - let
1332  23%                                  - unwind-protect
1332  23%                                   - progn
1332  23%                                    - save-excursion
1332  23%                                     - save-restriction
1301  23%                                      - let
1301  23%                                       - catch
1301  23%                                        - and
1301  23%                                         - org-indent-add-properties
1301  23%                                          - let
1301  23%                                           - unwind-protect
1301  23%                                            - progn
1301  23%                                             - save-excursion
1301  23%                                              - save-restriction
1301  23%                                               - let*
1296  23%                                                - let*
1296  23%                                                 - unwind-protect
1296  23%                                                  - progn
1296  23%                                                   - while
1296  23%                                                    - cond
1155  20%                                                       and
  87   1%                                                     - org-at-item-p
  83   1%                                                      - save-excursion
  80   1%                                                       - and
  65   1%                                                        - org-list-in-valid-context-p
  64   1%                                                         - not
  63   1%                                                          - org-in-block-p
  63   1%                                                           - let
  60   1%                                                            - unwind-protect
  60   1%                                                             - progn
  60   1%                                                              + catch
   8   0%                                                        + looking-at
  40   0%                                                     + org-indent-set-line-properties
   4   0%                                                     + let*
   4   0%                                                + or
   1   0%                                                + org-get-limited-outline-regexp
  30   0%                                      + let*
   1   0%                                      + if
   1   0%                               + while
   5   0%                             + if
  51   0%                    + and
  10   0%                    + if
   4   0%                    + org-element--cache-active-p
   3   0%                    + eq
 481   8%                   + setq
   1   0%                    setq
  14   0%                + let*
1036  18%           + org-backward-paragraph
 476   8%    + counsel-M-x
   3   0%    + next-line
   2   0%    + end-of-buffer
   1   0%    + previous-line
1917  34% - ...
1917  34%    Automatic GC
  17   0% + timer-event-handler
  12   0% + redisplay_internal (C function)
   1   0% + global-aggressive-indent-mode-check-buffers
   1   0% + emojify-update-visible-emojis-background-after-command

Memory Profiler Report

264,854,075  76% - command-execute
264,854,075  76%  - call-interactively
264,854,075  76%   - funcall-interactively
255,418,275  73%    - org-fill-paragraph
255,418,275  73%     - let
255,418,275  73%      - cond
255,204,659  73%       - let
255,204,659  73%        - unwind-protect
255,204,659  73%         - progn
255,204,659  73%          - while
180,115,491  51%           - org-backward-paragraph
180,115,491  51%            - if
180,115,491  51%             - while
180,115,491  51%              - org--backward-paragraph-once
176,778,067  50%               - save-restriction
176,778,067  50%                - cond
165,159,987  47%                 - let*
141,442,819  40%                  - org--paragraph-at-point
138,407,875  39%                   - let*
107,627,587  31%                    - org-element-at-point
106,599,043  30%                     - let
 60,513,047  17%                      - setq
 60,513,047  17%                       - if
 59,896,343  17%                        - condition-case
 56,847,671  16%                         - org-element--parse-to
 56,847,671  16%                          - catch
 26,082,351   7%                           - let
 22,117,552   6%                            - unwind-protect
 22,117,552   6%                             - progn
 20,683,728   5%                              - save-excursion
 20,683,728   5%                               - save-restriction
 15,229,632   4%                                - let*
  6,096,288   1%                                 + let
  3,049,728   0%                                   and
  2,037,024   0%                                   cond
 46,085,996  13%                      + if
 20,238,240   5%                    + if
  7,524,000   2%                    + cond
  9,968,048   2%                  + cond
    995,808   0%                    if
  2,436,160   0%                 + and
 73,443,920  21%           - org-fill-element
 71,424,848  20%            - let
 71,424,848  20%             - unwind-protect
 71,424,848  20%              - progn
 70,403,696  20%               - let
 66,939,368  19%                - save-excursion
 64,924,520  18%                 - org-element-at-point
 63,913,928  18%                  - let
 34,076,928   9%                   - setq
 34,076,928   9%                    - if
 33,458,112   9%                     - condition-case
 30,389,376   8%                      - org-element--parse-to
 30,389,376   8%                       - catch
 29,392,512   8%                        - let
 25,565,952   7%                         - unwind-protect
 25,565,952   7%                          - progn
 24,103,120   6%                           - save-excursion
 20,814,528   6%                            - save-restriction
 15,259,200   4%                             - let*
  6,083,616   1%                              + let
  3,057,120   0%                                and
  2,057,088   0%                                cond
 29,837,000   8%                   + if
  1,036,408   0%                + let*
    213,616   0%       + save-excursion
  9,014,486   2%    + counsel-M-x
    375,920   0%    + previous-line
     28,348   0%    + next-line
      9,984   0%    + org-end-of-line
      6,336   0%    + keyboard-quit
        484   0%    + end-of-buffer
        242   0%    + set-mark-command
 65,166,568  18% - redisplay_internal (C function)
 64,739,756  18%  - jit-lock-function
 64,739,756  18%   - jit-lock-fontify-now
 64,739,756  18%    - jit-lock--run-functions
 64,739,756  18%     - run-hook-wrapped
 64,739,756  18%      - #<compiled 0x19d0e565f4fbf57d>
 64,467,389  18%       - font-lock-fontify-region
 64,467,389  18%        - font-lock-default-fontify-region
 64,466,333  18%         - font-lock-fontify-keywords-region
 64,230,944  18%          + org-activate-links
      8,288   0%          + org-cite-activate
      6,944   0%          + org-raise-scripts
      6,176   0%          + org-fontify-meta-lines-and-blocks
      6,160   0%          + org-activate-dates
      5,440   0%          + org-activate-tags
      5,440   0%          + org-activate-footnote-links
      5,340   0%          + org-fontify-entities
      5,248   0%          + org-fontify-drawers
      5,248   0%          + org-fontify-macros
      5,248   0%          + org-font-lock-add-priority-faces
      5,120   0%          + org-font-lock-add-tag-faces
      5,120   0%          + org-do-emphasis-faces
      5,120   0%          + org-do-latex-and-related
      5,120   0%          + org-activate-code
      1,056   0%         + font-lock-unfontify-region
    254,519   0%       + emojify-redisplay-emojis-in-region
     15,736   0%       + valign-region
    239,728   0%  + eval
    178,900   0%  + #<compiled -0x194fe16722977b6d>
 16,698,568   4% + timer-event-handler
     42,080   0% + emojify-update-visible-emojis-background-after-command
     18,768   0% + winner-save-old-configurations
      3,180   0% + gui-set-selection
      2,154   0% + #<compiled -0x2222a52d2f12599>
          0   0%   ...