From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Lars Ingebrigtsen <larsi@gnus.org>
Cc: 22763@debbugs.gnu.org, Keith David Bershatsky <esq@lawlist.com>
Subject: bug#22763: 25.1.50; Feature Request -- A faster method to obtain line number at position.
Date: Sun, 07 Feb 2021 12:40:43 -0500 [thread overview]
Message-ID: <jwv35y722zo.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <87y2fz3lpe.fsf@gnus.org> (Lars Ingebrigtsen's message of "Sun, 07 Feb 2021 17:07:57 +0100")
> This takes 2.8s in Emacs 27 and 0.3s after the change:
>
> (with-temp-buffer
> (insert-file-contents "~/src/emacs/trunk/src/ChangeLog.11")
> (benchmark-run 1000
> (line-number-at-pos (point-max))))
>
> So that's nice. `line-number-at-pos' is used all over Emacs, but
> probably not in a loop a lot, so it probably doesn't make much
> difference, though.
Why is it faster?
Is it still always Θ(N) just with a smaller constant (if so, what makes
the constant smaller), or does it benefit from some kind of caching
(which I fail to see in the code) such that it's O(N) sometimes but much
faster other times (and if so, what are the cases that are sped up)?
Stefan
next prev parent reply other threads:[~2021-02-07 17:40 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-22 2:42 bug#22763: 25.1.50; Feature Request -- A faster method to obtain line number at position Keith David Bershatsky
2016-02-22 16:06 ` Eli Zaretskii
2021-02-07 15:07 ` Lars Ingebrigtsen
2021-02-07 15:44 ` Lars Ingebrigtsen
2021-02-07 16:07 ` Lars Ingebrigtsen
2021-02-07 17:40 ` Stefan Monnier [this message]
2021-02-07 17:45 ` Lars Ingebrigtsen
2021-02-07 18:07 ` Lars Ingebrigtsen
2021-02-07 18:09 ` Eli Zaretskii
2021-02-07 18:14 ` Lars Ingebrigtsen
2021-02-07 18:23 ` Lars Ingebrigtsen
2021-02-07 19:02 ` Eli Zaretskii
2021-02-07 19:06 ` Eli Zaretskii
2021-02-07 19:25 ` Lars Ingebrigtsen
2021-02-07 19:34 ` Lars Ingebrigtsen
2021-02-07 19:43 ` Eli Zaretskii
2021-02-07 19:42 ` Eli Zaretskii
2021-02-07 19:46 ` Lars Ingebrigtsen
2021-02-07 19:52 ` Eli Zaretskii
2021-02-07 21:52 ` Lars Ingebrigtsen
2021-02-07 21:58 ` Lars Ingebrigtsen
2021-02-08 3:34 ` Eli Zaretskii
2021-02-07 22:09 ` Philipp
2021-02-07 20:37 ` Stefan Monnier
2021-02-07 20:42 ` Lars Ingebrigtsen
2021-02-07 20:50 ` Eli Zaretskii
2021-02-07 21:36 ` Lars Ingebrigtsen
2021-02-08 15:04 ` Eli Zaretskii
2021-02-09 2:17 ` Katsumi Yamaoka
2021-02-09 7:13 ` Lars Ingebrigtsen
2021-05-19 23:55 ` Ben Levy via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-05-20 6:45 ` Eli Zaretskii
2021-05-20 7:27 ` Andreas Schwab
2021-05-20 7:35 ` Ben Levy via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-05-20 9:08 ` Eli Zaretskii
2021-05-20 9:03 ` Eli Zaretskii
2021-05-20 19:53 ` Ben Levy via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-05-20 20:09 ` Eli Zaretskii
2021-05-20 20:40 ` Ben Levy via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-05-21 5:46 ` Eli Zaretskii
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