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Subject: |
25.0.95; forward-comment backwards takes O(n^2) |
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Date: |
Sun, 17 Jul 2016 19:04:18 +0800 |
1. Use the attached file as an example, open it in emacs in ruby-mode
2. Move point to end of buffer and eval (forward-comment (- (point)))
The last step takes about 0.25 seconds on my MacBook 3 GHz Intel Core
i7. If you double the lines of comments, the time increase by 4 folds.
Any idea why forward-comment backwards is so slow?
Leo
tt.rb
Description: tt.rb
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--- Begin Message ---
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Subject: |
Re: bug#24012: 25.0.95; forward-comment backwards takes O(n^2) |
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Date: |
Fri, 08 Nov 2019 04:59:14 +0100 |
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User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) |
Stefan Kangas <address@hidden> writes:
> Dmitry Gutov <address@hidden> writes:
>
>> On 7/17/16 2:04 PM, Leo Liu wrote:
>>> 1. Use the attached file as an example, open it in emacs in ruby-mode
>>> 2. Move point to end of buffer and eval (forward-comment (- (point)))
>>> The last step takes about 0.25 seconds on my MacBook 3 GHz Intel Core
>>> i7. If you double the lines of comments, the time increase by 4 folds.
>>
>> FWIW, it looks fixed in the master branch now.
>>
>> Probably by 14b95587520959c5b54356547a0a69932a9bb480, so no idea what exactly
>> was causing it.
>
> Indeed. I only see O(n) on current master -- that is, if I use the
> source code from the original report, and double the amount of lines
> by C-x h M-w C-y, the time to evaluate this expression in a buffer
> only doubles:
>
> (progn (end-of-buffer) (forward-comment (- (point))))
>
> Leo, are you still seeing this issue? If I don't hear back within a
> couple of weeks, I'll just assume that this has been fixed and close
> this bug.
More information was requested, but none was given within 5 weeks, so
I'm closing this bug. If this is still an issue, please reopen the
bug report.
Best regards,
Stefan Kangas
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