bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Clément Pit-Claudel]

[-- Attachment #1: Type: text/plain, Size: 1960 bytes --]

Hi bug-gnu-emacs,

I have attached a profile in which Flyspell's flyspell-check-word-p consumes 89% of CPU time while typing text in a buffer.  This seems to be due to a call to sit-for in flyspell-check-word-p.  What is this sit-for there for?

- flyspell-post-command-hook                                     6077  89%
 - flyspell-check-word-p                                         6073  89%
  - sit-for                                                      6067  89%
   - read-event                                                  3826  56%
    + redisplay_internal (C function)                             128   1%
    + timer-event-handler                                          91   1%
    + fstar-subp-filter                                             3   0%
   - redisplay                                                   2205  32%
    + redisplay_internal (C function)                             100   1%
  + flyspell-get-not-casechars                                      2   0%
 + flyspell-check-pre-word-p                                        4   0%
+ command-execute                                                 220   3%
+ ...                                                             131   1%
+ timer-event-handler                                             116   1%
+ redisplay_internal (C function)                                 114   1%
+ company-post-command                                            102   1%
+ flycheck-perform-deferred-syntax-check                            5   0%
+ eldoc-pre-command-refresh-echo-area                               3   0%
  sml/generate-position-help                                        1   0%

I haven't spent much time investigating this issue yet, and my current repro isn't exactly reliable, but I was hoping that someone might be able to provide insight into Flyspell's behaviour before I dive to deep :) I did verify that disabling Flyspell fixed the issue.

Thanks!
Clément.

[-- Attachment #2: flyspell.prof --]
[-- Type: text/plain, Size: 35632 bytes --]


[profiler-profile "24.3" cpu #s(hash-table size 217 test equal rehash-size 1.5 rehash-threshold 0.8125 data ([redisplay sit-for execute-extended-command smex-read-and-run smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil] 13 [read-event sit-for execute-extended-command smex-read-and-run smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil] 22 [apply "#<compiled 0x46efc7>" redisplay_internal\ \(C\ function\) read-event sit-for execute-extended-command smex-read-and-run smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil] 1 [nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil] 2521 [redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil nil nil nil] 2105 [read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil nil nil nil] 3604 [sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil nil nil nil nil] 36 [json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let fstar-subp--query if fstar-subp--query-and-wait-1 let*] 6 ["#<compiled 0x11b1aef>" mapconcat rm--mode-list-as-string-list sml/generate-minor-modes eval posn-at-point company--col-row company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler read-event] 5 [company-pseudo-tooltip-show company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil] 16 [company--col-row company--row company--pseudo-tooltip-height company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command nil nil nil nil nil nil nil nil nil] 34 [company-fill-propertize company--create-lines company-pseudo-tooltip-edit company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company--perform company-post-command nil nil nil nil nil nil nil nil] 13 [font-lock-fontify-syntactically-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x12e23fd>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil] 18 [if and let "#<lambda 0x2bcdceff447a34>" funcall if "#<lambda 0x15c97795d86fa532>" funcall unwind-protect let* fstar-subp--process-response progn if let cond save-current-buffer] 1 [company-safe-substring company-fill-propertize company--create-lines company-pseudo-tooltip-edit company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company--perform company-post-command nil nil nil nil nil nil nil] 8 [font-lock-prepend-text-property font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x1495581>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil] 12 [while "#<lambda 0xe38a23f3eef61>" syntax-propertize internal--syntax-propertize skip-syntax-backward company-grab-symbol let progn unwind-protect let progn if cond progn if fstar-subp-company-backend] 3 [apply json-read json-read-array apply json-read json-read-array apply json-read json-read-object apply json-read condition-case progn if let* fstar-subp-json--read-response] 9 [font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x127a8b5>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil] 15 [rm-format-mode-line-entry mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil] 16 [json-encode-array json-encode-list json-encode "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq] 1 [font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0xc51b1f>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function posn-at-point company--col-row company--row company--pseudo-tooltip-height company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command] 8 [and while "#<lambda 0xe38a23f3eef61>" syntax-propertize internal--syntax-propertize skip-syntax-backward company-grab-symbol let progn unwind-protect let progn if cond progn if] 5 [mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil nil] 4 [company--force-sync company-call-backend company-calculate-candidates company--continue company--perform company-post-command nil nil nil nil nil nil nil nil nil nil] 6 [company--force-sync company-call-backend company-fetch-metadata company-echo-show apply timer-event-handler nil nil nil nil nil nil nil nil nil nil] 3 [redisplay--update-region-highlight run-hook-with-args redisplay--pre-redisplay-functions apply "#<compiled 0x46efc7>" redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil] 1 ["#<compiled 0x18391a5>" json-read-from-string json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let fstar-subp--query let*] 1 [pos-tip-show company-quickhelp--show apply timer-event-handler nil nil nil nil nil nil nil nil nil nil nil nil] 5 [jit-lock-function posn-at-point pos-tip-compute-pixel-position pos-tip-show-no-propertize pos-tip-show company-quickhelp--show apply timer-event-handler nil nil nil nil nil nil nil nil] 3 [syntax-ppss prettify-symbols-default-compose-p prettify-symbols--compose-symbol eval font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x10aae01>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) redisplay pos-tip-compute-pixel-position pos-tip-show-no-propertize] 4 [redisplay pos-tip-compute-pixel-position pos-tip-show-no-propertize pos-tip-show company-quickhelp--show apply timer-event-handler nil nil nil nil nil nil nil nil nil] 16 [face-attribute face-attr-match-p frame-set-background-mode internal-set-lisp-face-attribute set-face-attribute apply face-spec-set-2 face-spec-recalc face-set-after-frame-default x-show-tip pos-tip-show-no-propertize pos-tip-show company-quickhelp--show apply timer-event-handler nil] 11 [check-face face-name set-face-attribute-from-resource set-face-attributes-from-resources make-face-x-resource-internal face-spec-recalc frame-set-background-mode internal-set-lisp-face-attribute set-face-attribute apply face-spec-set-2 face-spec-recalc face-set-after-frame-default x-show-tip pos-tip-show-no-propertize pos-tip-show] 4 [facep check-face face-name set-face-attribute-from-resource set-face-attributes-from-resources make-face-x-resource-internal face-spec-recalc frame-set-background-mode internal-set-lisp-face-attribute set-face-attribute apply face-spec-set-2 face-spec-recalc face-set-after-frame-default x-show-tip pos-tip-show-no-propertize] 8 [set-face-attribute apply face-spec-reset-face face-spec-recalc frame-set-background-mode internal-set-lisp-face-attribute set-face-attribute apply face-spec-set-2 face-spec-recalc face-set-after-frame-default x-show-tip pos-tip-show-no-propertize pos-tip-show company-quickhelp--show apply] 4 [set-face-attribute-from-resource set-face-attributes-from-resources make-face-x-resource-internal face-spec-recalc face-set-after-frame-default x-show-tip pos-tip-show-no-propertize pos-tip-show company-quickhelp--show apply timer-event-handler nil nil nil nil nil] 3 [facep check-face face-name set-face-attribute-from-resource set-face-attributes-from-resources make-face-x-resource-internal face-spec-recalc face-set-after-frame-default x-show-tip pos-tip-show-no-propertize pos-tip-show company-quickhelp--show apply timer-event-handler nil nil] 4 [set-face-attribute apply face-spec-reset-face face-spec-recalc face-set-after-frame-default x-show-tip pos-tip-show-no-propertize pos-tip-show company-quickhelp--show apply timer-event-handler nil nil nil nil nil] 12 [ispell-decode-string ispell-get-decoded-string ispell-get-otherchars flyspell-check-pre-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil nil nil] 4 [funcall eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil] 4 [rm-format-mode-line-entry mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 12 [json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let fstar-subp--query if fstar-subp-company--async-lookup fstar-subp-company--async-meta] 3 [ruler-mode-ruler funcall eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil] 4 [apply json-read json-read-from-string json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query] 3 [sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil] 4 [syntax-ppss font-lock-fontify-syntactically-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x110b819>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil] 12 [sml/generate-modified-status eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil] 22 [flycheck-finish-current-syntax-check flycheck-report-buffer-checker-status apply "#<compiled 0x1203ad3>" funcall let* if fstar-subp--flycheck-continuation apply "#<compiled 0x1203e91>" funcall unwind-protect let* fstar-subp--process-response progn if] 3 [fstar-subp-next-block-sep let while let save-excursion fstar-subp--next-unprocessed-start let if fstar-subp--start-syntax-check flycheck-syntax-check-start flycheck-start-current-syntax-check flycheck-buffer flycheck-buffer-automatically flycheck-perform-deferred-syntax-check nil nil] 5 ["#<compiled 0x11b1aef>" mapconcat rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil] 8 [file-remote-p redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil nil nil nil nil] 4 [syntax-ppss font-lock-fontify-syntactically-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x19ed3cb>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) nil nil nil nil nil nil] 8 [and if fstar-subp-start let fstar-subp--query if fstar-subp--query-and-wait-1 let* fstar-subp--query-and-wait let* progn if if let fstar--eldoc-function eldoc-print-current-symbol-info] 4 [self-insert-command funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil nil nil nil nil] 1 [apply eldoc-minibuffer-message "#<compiled 0x28eb17>" apply let if fstar--eldoc-truncate-message apply eldoc-message eldoc-print-current-symbol-info "#<compiled 0x28ea7d>" apply timer-event-handler nil nil nil] 3 [flycheck-clear-idle-change-timer flycheck-handle-idle-change apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil] 1 [ruler-mode-ruler funcall eval redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil nil nil] 17 ["#<compiled 0x11b1b5f>" mapcar rm--remove-hidden-modes rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil] 8 [json-read-escaped-char json-read-string apply json-read json-read-object apply json-read json-read-array apply json-read json-read-object apply json-read condition-case progn if] 3 ["#<compiled 0x11b1aef>" mapconcat rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 12 [sml/generate-modified-status eval format-mode-line sml/fill-width-available sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil] 4 [rm-format-mode-line-entry mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 4 [sml/generate-position-help nil nil nil nil nil nil nil nil nil nil nil nil nil nil nil] 1 [while if fstar-subp--query-and-wait-1 let* fstar-subp--query-and-wait let* progn if if let fstar--eldoc-function eldoc-print-current-symbol-info "#<compiled 0x28ea7d>" apply timer-event-handler nil] 3 [sml/fill-width-available sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil] 4 [apply let* save-current-buffer fstar--log progn if if let if save-current-buffer fstar-subp-process-queue apply timer-event-handler nil nil nil] 4 [flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil nil nil nil nil nil] 4 [fstar-subp-filter accept-process-output while if fstar-subp--query-and-wait-1 let* fstar-subp--query-and-wait let fstar-subp-company-candidates cond progn if fstar-subp-company-backend apply company-call-backend-raw company--fetch-candidates] 1 ["#<compiled 0x11b1aef>" mapconcat rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 19 [cdr let* let cond let* format my-flycheck-mode-line-status-text eval format-mode-line rm-format-mode-line-entry mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event] 8 [json-encode "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if] 3 [font-lock-fontify-syntactically-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x10fc961>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil] 12 [save-current-buffer progn if let if let if let let let progn if let* while fstar-subp-json--find-response if] 2 [json-join json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let fstar-subp--query if fstar-subp--query-and-wait-1 let* fstar-subp--query-and-wait let*] 3 [font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x1a832ff>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil] 4 [sml/generate-modified-status eval format-mode-line sml/fill-width-available sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil] 8 [apply eldoc-minibuffer-message "#<compiled 0x28eb17>" apply let if fstar--eldoc-truncate-message apply eldoc-message eldoc-pre-command-refresh-echo-area nil nil nil nil nil nil] 3 [company--col-row company--row company--pseudo-tooltip-height company-pseudo-tooltip-show company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook] 4 [company-buffer-lines company-pseudo-tooltip-show company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil] 4 [rm--propertize mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval posn-at-point company--col-row company--row company--pseudo-tooltip-height company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command nil nil nil] 6 ["#<compiled 0x1a84eb1>" funcall if let "#<lambda 0x32a0b8f8447a34>" funcall if "#<lambda 0x15c97795d86fa532>" funcall unwind-protect let* fstar-subp--process-response progn if let cond] 2 [apply "#<compiled 0x46efc7>" redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil] 4 [apply json-read json-read-object apply json-read json-read-array apply json-read json-read-object apply json-read condition-case progn if let* fstar-subp-json--read-response] 2 [funcall eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil] 4 [font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x17b0953>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil] 8 [and while if fstar-subp--query-and-wait-1 let* fstar-subp--query-and-wait let fstar-subp-company-candidates cond progn if fstar-subp-company-backend apply company-call-backend-raw company--fetch-candidates company-calculate-candidates] 4 [font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x1a8bbb7>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil] 4 [progn if let* let cond let* format my-flycheck-mode-line-status-text eval format-mode-line rm-format-mode-line-entry mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\)] 4 [run-hook-with-args jit-lock-after-change insert let* save-current-buffer fstar--log progn if progn if fstar-subp-filter read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil] 3 [sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil] 12 [rm--propertize mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 4 [tramp-flush-file-function kill-buffer "#<compiled 0x15eeb25>" json-read-from-string json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let] 3 [setq while let fstar-find-id-maybe-type fstar-find-id-with-type font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0xc53f21>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) redisplay sit-for] 3 [company--should-complete company--perform company-auto-begin company-idle-begin apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 3 [redisplay sit-for battery-update-handler apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil] 22 [jit-lock-function redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil nil nil nil nil] 8 [eq or save-excursion or and setq while let fstar-find-id-maybe-type fstar-find-id-with-type font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x16367f9>" run-hook-wrapped jit-lock--run-functions] 3 [syntax-ppss prettify-symbols-default-compose-p prettify-symbols--compose-symbol eval font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x14033f5>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) nil nil nil] 4 ["#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let] 3 [sml/generate-modified-status eval format-mode-line sml/fill-width-available sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil] 4 [sml/generate-modified-status eval redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil nil nil nil] 5 ["#<compiled 0x46efc7>" redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil nil] 2 [rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil] 4 [company--col-row company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil] 3 [eval rm--propertize mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil] 4 [font-lock-fontify-syntactically-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x1537351>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil] 4 [sml/fill-width-available sml/generate-minor-modes eval posn-at-point company--col-row company--row company--pseudo-tooltip-height company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command nil nil nil nil nil] 2 [syntax-ppss let* let cond while "#<lambda 0xe38a23f3eef61>" syntax-propertize internal--syntax-propertize skip-syntax-backward company-grab-symbol let progn unwind-protect let progn if] 1 [apply derived-mode-p save-place-to-alist kill-buffer "#<compiled 0x1ae204b>" company-safe-substring company-modify-line company--replacement-string apply company-pseudo-tooltip-edit company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company--perform company-post-command nil] 2 ["#<compiled 0x12030bd>" json-read-from-string json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let fstar-subp--query if] 2 [company--clean-string company--create-lines company-pseudo-tooltip-edit company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company--perform company-post-command nil nil nil nil nil nil nil nil] 4 [tramp-flush-file-function kill-buffer "#<compiled 0x193783f>" json-read-from-string json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let] 2 [beginning-of-visual-line company-pseudo-tooltip-guard company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command nil nil nil nil nil nil nil nil nil nil] 9 [json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let fstar-subp--query let* fstar-subp-peek-region if] 3 [let* save-current-buffer fstar--log progn if cond let* fstar-subp-json--read-response and let* while fstar-subp-json--find-response if fstar-subp-find-response save-current-buffer progn] 2 [redisplay--update-region-highlight run-hook-with-args redisplay--pre-redisplay-functions apply "#<compiled 0x46efc7>" redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 4 [company--force-sync company-call-backend company-fetch-metadata company-echo-show apply timer-event-handler read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil] 6 [funcall eval redisplay_internal\ \(C\ function\) nil nil nil nil nil nil nil nil nil nil nil nil nil] 4 [company-grab-symbol let progn unwind-protect let progn if cond progn if fstar-subp-company-backend company--begin-new company--perform company-auto-begin company-idle-begin apply] 2 [while if fstar-subp--query-and-wait-1 let* fstar-subp--query-and-wait let fstar-subp-company-candidates cond progn if fstar-subp-company-backend apply company-call-backend-raw company--fetch-candidates company-calculate-candidates company--begin-new] 2 [sml/fill-width-available sml/generate-minor-modes eval posn-at-point company--col-row company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler read-event sit-for flyspell-check-word-p] 4 [font-lock-prepend-text-property font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x121f07d>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil] 4 [fstar-find-id-with-type font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x1960333>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function posn-at-point company--col-row company--row company--pseudo-tooltip-height company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends] 4 [apply let* save-current-buffer fstar--log progn if cond let* fstar-subp-json--read-response and let* while fstar-subp-json--find-response if fstar-subp-find-response save-current-buffer] 4 [apply "#<compiled 0x46efc7>" redisplay_internal\ \(C\ function\) redisplay sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil] 4 [apply json-read json-read-array apply json-read json-read-object apply json-read condition-case progn if let* fstar-subp-json--read-response and let* while] 1 [company--col-row company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler nil nil nil nil nil nil nil] 4 [company-pseudo-tooltip-show company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler nil nil nil nil nil nil nil] 4 [ispell-decode-string ispell-get-decoded-string flyspell-get-not-casechars flyspell-check-word-p flyspell-post-command-hook nil nil nil nil nil nil nil nil nil nil nil] 2 [rm-format-mode-line-entry mapcar rm--mode-list-as-string-list sml/generate-minor-modes eval posn-at-point company--col-row company-pseudo-tooltip-show-at-point company-pseudo-tooltip-frontend company-pseudo-tooltip-unless-just-one-frontend company-call-frontends company-post-command company-idle-begin apply timer-event-handler read-event] 5 [get-buffer-create generate-new-buffer json-read-from-string json-encode-key "#<compiled 0x391c33>" mapcar json-encode-alist json-encode-list json-encode let fstar-subp--serialize-query setq progn if let fstar-subp--query] 2 [setq while let fstar-find-id-maybe-type fstar-find-id-with-type font-lock-fontify-keywords-region font-lock-default-fontify-region font-lock-fontify-region "#<compiled 0x465e09>" run-hook-wrapped jit-lock--run-functions jit-lock-fontify-now jit-lock-function posn-at-point company--col-row company--row] 3 [font-lock-default-fontify-region font-lock-fontify-region font-lock-default-fontify-buffer "#<compiled 0x4f4bc5>" font-lock-ensure if save-current-buffer fstar-highlight-string concat fstar-lookup-result-sig cond funcall fstar-subp-company--meta-continuation apply "#<compiled 0x17b0a23>" funcall] 2 [file-remote-p sml/generate-modified-status eval format-mode-line sml/fill-width-available sml/generate-minor-modes eval redisplay_internal\ \(C\ function\) read-event sit-for flyspell-check-word-p flyspell-post-command-hook nil nil nil nil] 4 [let fstar-subp--query let* fstar-subp-peek-region if let if fstar-subp--start-syntax-check flycheck-syntax-check-start flycheck-start-current-syntax-check flycheck-buffer flycheck-buffer-automatically flycheck-handle-idle-change apply timer-event-handler nil] 4 ["#<compiled 0xdb1dc3>" mapatoms smex-detect-new-commands smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil nil] 6 [mapatoms smex-rebuild-cache smex-update smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil nil] 20 ["#<compiled 0x48bd29>" mapatoms smex-rebuild-cache smex-update smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil] 4 [smex-sorting-rules sort smex-rebuild-cache smex-update smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil] 4 [sort smex-rebuild-cache smex-update smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil nil] 4 [smex-rebuild-cache smex-update smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively command-execute nil nil nil nil nil nil nil] 4 [mapc ido-set-matches-1 ido-set-matches "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex funcall-interactively "#<subr call-interactively>"] 4 ["#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply call-interactively] 6 [ido-set-matches-1 ido-set-matches ido-exhibit read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex funcall-interactively] 4 [read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex funcall-interactively "#<subr call-interactively>" ad-Advice-call-interactively apply] 80 ["#<compiled 0xee57f5>" mapc ido-set-matches-1 ido-set-matches ido-exhibit read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run] 5 [ido-word-matching-substring mapcar ido-find-common-substring ido-set-common-completion ido-exhibit read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run] 4 [ido-set-matches ido-exhibit read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex funcall-interactively "#<subr call-interactively>"] 2 [mapc ido-set-matches-1 ido-set-matches ido-exhibit read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex] 10 [sml/generate-modified-status eval redisplay_internal\ \(C\ function\) read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex funcall-interactively] 4 ["#<compiled 0xee5823>" mapc ido-set-matches-1 ido-set-matches ido-exhibit read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run] 8 ["#<compiled 0x46efc7>" redisplay_internal\ \(C\ function\) read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run smex funcall-interactively "#<subr call-interactively>"] 1 [window-current-scroll-bars ruler-mode-ruler funcall eval redisplay_internal\ \(C\ function\) read-from-minibuffer "#<compiled 0xedc525>" ad-Advice-ido-read-internal apply ido-read-internal "#<compiled 0xeea9e9>" ad-Advice-ido-completing-read apply ido-completing-read smex-completing-read smex-read-and-run] 5 [Automatic\ GC] 86)) (22770 32098 861101 964000) nil]

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Clément Pit-Claudel]

The relevant piece of code seems to be this:

      (cond
       ((get this-command 'flyspell-deplacement)
	(not (eq flyspell-previous-command this-command)))
       ((get this-command 'flyspell-delayed)
	;; The current command is not delayed, that
	;; is that we must check the word now.
	(and (not unread-command-events)
	     (sit-for flyspell-delay)))
       (t t)))

But the condition and the comment seem at odds, and it doesn't say much about why it calls `sit-for`.

Clément.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Eli Zaretskii]

> From: Clément Pit-Claudel <cpitclaudel@gmail.com>
> Date: Sat, 15 Apr 2017 16:33:56 -0400
> 
> The relevant piece of code seems to be this:
> 
>       (cond
>        ((get this-command 'flyspell-deplacement)
> 	(not (eq flyspell-previous-command this-command)))
>        ((get this-command 'flyspell-delayed)
> 	;; The current command is not delayed, that
> 	;; is that we must check the word now.
> 	(and (not unread-command-events)
> 	     (sit-for flyspell-delay)))
>        (t t)))
> 
> But the condition and the comment seem at odds, and it doesn't say much about why it calls `sit-for`.

I'm not quite sure what needs to be explained.  I think the doc string
of flyspell-delay and flyspell-default-delayed-commands tell the whole
story; if something is unclear there, please say what is unclear.

If you want to see this feature in action, turn on Flyspell, then type
something like "ssss", and then wait _without_ typing any non-word
character.  You will see that the mis-spelled word is marked only
after 3 sec, the default value of flyspell-delay.  Then contrast that
with the same word with a space typed after it.

IOW, this is a feature designed to avoid annoying users who type
slowly or make short breaks after typing only part of a word.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Clément Pit-Claudel]

On 2017-04-17 03:14, Eli Zaretskii wrote:
>> But the condition and the comment seem at odds, and it doesn't say much about why it calls `sit-for`.
> 
> I'm not quite sure what needs to be explained.  I think the doc string
> of flyspell-delay and flyspell-default-delayed-commands tell the whole
> story; if something is unclear there, please say what is unclear.

The code reads (cond ((get this-command 'flyspell-delayed) …)), but the comment says "The current command is not delayed".  Does a non-nil flycheck-delayed really mean that the command is *not* delayed?

> If you want to see this feature in action, turn on Flyspell, then type
> something like "ssss", and then wait _without_ typing any non-word
> character.  You will see that the mis-spelled word is marked only
> after 3 sec, the default value of flyspell-delay.  Then contrast that
> with the same word with a space typed after it.

Thanks! I don't expect that this feature is intended to slow down typing, though, right?  In the example I posted it makes typing painfully slow.

Clément.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Eli Zaretskii]

> Cc: 26525@debbugs.gnu.org
> From: Clément Pit-Claudel <cpitclaudel@gmail.com>
> Date: Mon, 17 Apr 2017 09:29:20 -0400
> 
> On 2017-04-17 03:14, Eli Zaretskii wrote:
> >> But the condition and the comment seem at odds, and it doesn't say much about why it calls `sit-for`.
> > 
> > I'm not quite sure what needs to be explained.  I think the doc string
> > of flyspell-delay and flyspell-default-delayed-commands tell the whole
> > story; if something is unclear there, please say what is unclear.
> 
> The code reads (cond ((get this-command 'flyspell-delayed) …)), but the comment says "The current command is not delayed".  Does a non-nil flycheck-delayed really mean that the command is *not* delayed?

I think the comment should be moved 2 lines below its current place,
that's all.

> > If you want to see this feature in action, turn on Flyspell, then type
> > something like "ssss", and then wait _without_ typing any non-word
> > character.  You will see that the mis-spelled word is marked only
> > after 3 sec, the default value of flyspell-delay.  Then contrast that
> > with the same word with a space typed after it.
> 
> Thanks! I don't expect that this feature is intended to slow down typing, though, right?  In the example I posted it makes typing painfully slow.

I didn't see any example in your OP, only a profile.  What did I miss?

And no, this is not supposed to slow down typing in any significant
way, as long as you type, because sit-for is supposed to return as
soon as input is available.  Your complaint was about CPU usage, not
about time delays, AFAIU.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Clément Pit-Claudel]

On 2017-04-17 10:25, Eli Zaretskii wrote:
>> Thanks! I don't expect that this feature is intended to slow down typing, though, right?  In the example I posted it makes typing painfully slow.
> I didn't see any example in your OP, only a profile.  What did I miss?
> 
> And no, this is not supposed to slow down typing in any significant
> way, as long as you type, because sit-for is supposed to return as
> soon as input is available.  Your complaint was about CPU usage, not
> about time delays, AFAIU.

Indeed, there was only a profile; I don't have a good repro yet.  In that case, flyspell was slowing things down a lot, and the complaint was indeed about delays.
Sorry for being unclear.

Clément.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Damien Cassou]

> I have attached a profile in which Flyspell's flyspell-check-word-p
> consumes 89% of CPU time while typing text in a buffer. […]

This happened to me in the past then stopped for months. Now it happens
again and is really annoying. Emacs regularly freezes for around 5
seconds when I manipulate text.

-- 
Damien Cassou
http://damiencassou.seasidehosting.st

"Success is the ability to go from one failure to another without
losing enthusiasm." --Winston Churchill

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Stefan Kangas]

Clément Pit-Claudel <cpitclaudel@gmail.com> writes:

> On 2017-04-17 10:25, Eli Zaretskii wrote:
>>> Thanks! I don't expect that this feature is intended to slow down typing, though, right?  In the example I posted it makes typing painfully slow.
>> I didn't see any example in your OP, only a profile.  What did I miss?
>>
>> And no, this is not supposed to slow down typing in any significant
>> way, as long as you type, because sit-for is supposed to return as
>> soon as input is available.  Your complaint was about CPU usage, not
>> about time delays, AFAIU.
>
> Indeed, there was only a profile; I don't have a good repro yet.  In that case, flyspell was slowing things down a lot, and the complaint was indeed about delays.
> Sorry for being unclear.

That was 3 years ago.  Are you still seeing this on a recent version of
Emacs, such as the recently released 27.1?

Best regards,
Stefan Kangas

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Stefan Kangas]

Damien Cassou <damien@cassou.me> writes:

>> I have attached a profile in which Flyspell's flyspell-check-word-p
>> consumes 89% of CPU time while typing text in a buffer. […]
>
> This happened to me in the past then stopped for months. Now it happens
> again and is really annoying. Emacs regularly freezes for around 5
> seconds when I manipulate text.

That was 3 years ago.  Are you still seeing this on a recent version of
Emacs, such as the recently released 27.1?

Best regards,
Stefan Kangas

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Damien Cassou]

Stefan Kangas <stefan@marxist.se> writes:
> That was 3 years ago.  Are you still seeing this on a recent version of
> Emacs, such as the recently released 27.1?

This hasn't happened for some time.

-- 
Damien Cassou

"Success is the ability to go from one failure to another without
losing enthusiasm." --Winston Churchill

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Clément Pit-Claudel]

On 8/28/20 8:35 AM, Damien Cassou wrote:
> Stefan Kangas <stefan@marxist.se> writes:
>> That was 3 years ago.  Are you still seeing this on a recent version of
>> Emacs, such as the recently released 27.1?
> 
> This hasn't happened for some time.
> 

There was a report of a similar issue on reddit recently, but it hasn't happened to me of late.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Stefan Kangas]

tags 26525 + unreproducible
thanks

Clément Pit-Claudel <cpitclaudel@gmail.com> writes:

> On 8/28/20 8:35 AM, Damien Cassou wrote:
>> Stefan Kangas <stefan@marxist.se> writes:
>>> That was 3 years ago.  Are you still seeing this on a recent version of
>>> Emacs, such as the recently released 27.1?
>>
>> This hasn't happened for some time.
>>
>
> There was a report of a similar issue on reddit recently, but it hasn't happened to me of late.

You wouldn't happen to have a link to the relevant thread?  I tried
searching the web but couldn't find anything.

I'm marking this bug as unreproducible for now.  Please report back if
you see this again or can provide any more information.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Clément Pit-Claudel]

On 8/29/20 12:27 PM, Stefan Kangas wrote:
> You wouldn't happen to have a link to the relevant thread?  I tried
> searching the web but couldn't find anything.

https://www.reddit.com/r/emacs/comments/i96lbo/flyspell_consuming_most_of_my_resources_why_oo/ , sorry for not including it the first time.

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Nick H]

> I'm marking this bug as unreproducible for now.  Please report back
> if you see this again or can provide any more information.

I just bumped into this bug on 27.1 with the same symptoms - typing lag
after activating flyspell-mode. 

I took a couple of profiles - the first when lag was apparent and
another after clearing the lag by toggling flyspell-mode.

Both profiles show a similar result, so the "high cpu" in sit-for might
be a red-herring.

Profile 1 - with lag
  - flyspell-post-command-hook                     1146  92%
   - flyspell-check-word-p                         1120  90%
    - sit-for                                      1117  90%
     - redisplay                                    551  44%
      + redisplay_internal (C function)               1   0%
       read-event                                   390  31%
    - flyspell-get-not-casechars                      1   0%
       ispell-get-decoded-string                      1   0%
   + flyspell-word                                    8   0%
   + flyspell-check-pre-word-p                        3   0%
  + command-execute                                  65   5%
  + ...                                              22   1%
  + undo-auto--add-boundary                           1   0%

Profile 2 - without lag
  - flyspell-post-command-hook                     3507  94%
   - flyspell-check-word-p                         3432  92%
    - sit-for                                      3414  92%
     - redisplay                                   1660  44%
      + redisplay_internal (C function)               3   0%
     + read-event                                  1317  35%
    + ispell-get-otherchars                           6   0%
    + flyspell-get-not-casechars                      5   0%
   + flyspell-word                                   17   0%
   + flyspell-check-pre-word-p                       13   0%
  + command-execute                                  93   2%
  + ...                                              87   2%
  + timer-event-handler                               3   0%
    undo-auto--add-boundary                           2   0%
    tooltip-hide                                      1   0%

Nick

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Stefan Kangas]

Nick H <nick@tenpoint.co.nz> writes:

> I just bumped into this bug on 27.1 with the same symptoms - typing lag
> after activating flyspell-mode.

What is your ispell/flyspell configuration?

Do you have any ideas about how to reproduce it, or could you say
something about the circumstances under which you saw this?

bug#26525: `sit-for' in Flyspell slows typing down, hogs 90% of CPU

[Nick Helm]

On Thu, 2020-09-03 at 03:19 -0700, Stefan Kangas wrote:
> Nick H <nick@tenpoint.co.nz> writes:
> 
> > I just bumped into this bug on 27.1 with the same symptoms - typing
> > lag after activating flyspell-mode.
> 
> What is your ispell/flyspell configuration?

Nothing unusual:

grep -C2 -E \(ispell\|flyspell\) ~/.config/emacs/init.el

  ; spelling
  (setq ispell-choices-win-default-height 2)
  (setq ispell-dictionary "en_NZ")
  (setq ispell-personal-dictionary (concat nh-etc "hunspell-dict"))
  (setq ispell-program-name "hunspell")
  (setq ispell-dictionary-alist
        '(("en_NZ" "[[:alpha:]]" "[^[:alpha:]]" "[']" t nil t utf-8)))
  (with-eval-after-load 'flyspell
    (progn
      (define-key 
         flyspell-mouse-map [down-mouse-3] #'flyspell-correct-word)
      (define-key 
         flyspell-mouse-map [mouse-3] nil)))

> Do you have any ideas about how to reproduce it, or could you say
> something about the circumstances under which you saw this?

The lead-up was pretty mundane - I visited an elisp file, set the 
region to a block of text, M-x write-region, C-x C-f the resulting
file, M-x vi-l-m, a few edits, M-x flys-buf, M-x flys-mod --> lag

I tried to reproduce the problem, but no success. Sorry.