Re: Markers in a gap array

[Ihor Radchenko <yantar92@posteo.net>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> There's no free lunch, so this comes at the cost of slowing down other
> marker operations, which is why I'd like to hear about your experience.
> ...
> So, for instance, `save-excursion` used to do a `copy-marker` followed
> by a (set-marker m nil), both of which were, typically, O(1) and are now
> made slower.

First experience - severe performance degradation compared to master.

Some perf stats:

;; Switch to todo and mark next 3 times, on branch
    ;; 28.72%  emacs            emacs                                      [.] markers_sanity_check
    ;; 11.83%  emacs            emacs                                      [.] Fmemq
    ;;  5.31%  emacs            emacs                                      [.] process_mark_stack
    ;;  2.59%  emacs            emacs                                      [.] re_match_2_internal
    ;;  2.47%  emacs            emacs                                      [.] buf_bytepos_to_charpos
    ;;  1.60%  emacs            emacs                                      [.] Ffuncall
    ;;  1.56%  emacs            emacs                                      [.] vector_marked_p

;; master
    ;; 14.31%  emacs            emacs                                          [.] Fmemq
    ;; 11.18%  emacs            emacs                                          [.] re_match_2_internal
    ;;  3.97%  emacs            emacs                                          [.] buf_bytepos_to_charpos
    ;;  2.60%  emacs            emacs                                          [.] process_mark_stack
    ;;  2.00%  emacs            emacs                                          [.] scan_sexps_forward

;; Just building agenda, on branch
    ;; 24.69%  emacs         emacs                                           [.] markers_sanity_check
    ;; 11.32%  emacs         emacs                                           [.] re_search_2
    ;;  6.08%  emacs         emacs                                           [.] re_match_2_internal
    ;;  4.57%  emacs         emacs                                           [.] process_mark_stack
    ;;  3.61%  emacs         emacs                                           [.] funcall_subr
    ;;  2.98%  emacs         emacs                                           [.] Ffuncall
    ;;  2.79%  emacs         emacs                                           [.] Fmemq
    ;;  2.73%  emacs         emacs                                           [.] buf_bytepos_to_charpos
    ;;  2.38%  emacs         emacs                                           [.] buf_charpos_to_bytepos

;; Just building agenda, master
    ;; 13.56%  emacs           emacs                                          [.] re_match_2_internal
    ;; 12.02%  emacs           emacs                                          [.] exec_byte_code
    ;;  7.92%  emacs           emacs                                          [.] re_search_2
    ;;  6.98%  emacs           emacs                                          [.] Fmemq
    ;;  5.15%  emacs           emacs                                          [.] process_mark_stack
    ;;  4.60%  emacs           emacs                                          [.] funcall_subr
    ;;  2.58%  emacs           emacs                                          [.] Ffuncall
    ;;  1.93%  emacs           emacs                                          [.] funcall_general
    ;;  1.33%  emacs           org-element-ast-1c181933-d46555e0.eln          [.] F6f72672d656c656d656e742d74797065_org_element_type_0
    ;;  1.26%  emacs           emacs                                          [.] plist_get
    ;;  1.22%  emacs           emacs                                          [.] assq_no_quit
    ;;  1.22%  emacs           emacs                                          [.] buf_bytepos_to_charpos
    ;;  1.02%  emacs           emacs                                          [.] vector_marked_p
    ;;  0.95%  emacs           emacs                                          [.] buf_charpos_to_bytepos



-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
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