--- Begin Message ---
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Subject: |
23.2; slow ansi-color-apply |
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Date: |
Thu, 23 Sep 2010 10:15:41 +0100 |
I have found ansi-color-apply very expensive and slow.
To test this, do the following
(remove-hook 'eshell-output-filter-functions 'eshell-handle-ansi-color)
(add-hook 'eshell-preoutput-filter-functions 'ansi-color-apply)
and do something in eshell that can output a large coloured text such
as:
cd /usr/include; ack time
where ack is a single file perl script from http://betterthangrep.com/.
The CPU usage should shoot up to very high.
The following version (after brief testing) seems to be noticeably
faster.
(defun ansi-color-apply* (string)
"A more efficient implementation of `ansi-color-apply' (which see)."
(let ((face (car ansi-color-context))
start end fragment escape-sequence)
;; If context was saved and is a string, prepend it.
(if (cadr ansi-color-context)
(setq string (concat (cadr ansi-color-context) string)
ansi-color-context nil))
(with-temp-buffer
(insert string)
(setq start (point-min-marker))
(goto-char start)
(while (re-search-forward ansi-color-drop-regexp nil t)
(replace-match ""))
(goto-char start)
;; Find the next escape sequence.
(while (re-search-forward ansi-color-regexp nil t)
(setq end (match-beginning 0))
(when face
(put-text-property start end 'ansi-color t)
(put-text-property start end 'face face))
(setq start (copy-marker (match-end 0)))
(setq escape-sequence (match-string 1))
(replace-match "")
(setq face (ansi-color-apply-sequence escape-sequence face)))
;; search for the possible start of a new escape sequence
(if (re-search-forward "\033" nil t)
(setq end (match-beginning 0)
fragment (buffer-substring end (point-max)))
(setq end (point-max)))
;; if the rest of the string should have a face, put it there
(when face
(put-text-property start end 'ansi-color t)
(put-text-property start end 'face face))
;; save context
(if (or face fragment)
(setq ansi-color-context (list face fragment))
(setq ansi-color-context nil))
(buffer-string))))
Leo
--- End Message ---
--- Begin Message ---
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Subject: |
Re: bug#7089: 23.2; slow ansi-color-apply |
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Date: |
Thu, 25 Nov 2010 14:30:54 +0000 |
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User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.2 (Mac OS X 10.6.5) |
On 2010-10-31 19:10 +0000, Stefan Monnier wrote:
>> Do you know for sure string-match is slower (more CPU intensive) than
>> re-search-forward?
>
> They should be largely equivalent. The difference between the two codes
> might be due to replace-match and substring. I.e. the original
> ansi-color-apply should be at least as efficient as your code (if not
> more) in the case where there are no SGR escape sequences.
>
>
> Stefan
I was setting out to profile the two versions of the function and
unfortunately I was not able to see the CPU shootup mentioned in the
first message. My result shows my version of ansi-color-apply is almost
twice as slow as the original one. (The code and data used for profiling
are attached.)
So please ignore this bug report.
Leo
ansi-color-test.el
Description: ansi-color-test.el
ansi-test.txt
Description: ansi-test.txt
--- End Message ---