GNU bug report logs - #57079
29.0.50; Performance of seq-uniq is not very good

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Package: emacs;

Reported by: Stefan Kangas <stefan <at> marxist.se>

Date: Tue, 9 Aug 2022 16:12:02 UTC

Severity: minor

Found in version 29.0.50

Fixed in version 29.1

Done: Lars Ingebrigtsen <larsi <at> gnus.org>

Bug is archived. No further changes may be made.

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From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 57079 <at> debbugs.gnu.org, stefan <at> marxist.se
Subject: bug#57079: 29.0.50; Performance of seq-uniq is not very good
Date: Tue, 09 Aug 2022 19:21:24 +0200

Eli Zaretskii <eliz <at> gnu.org> writes:

> No one said that was a problem in these cases.

I haven't audited the callers, but changing code that used to be
non-destructive to be destructive isn't to be taken lightly.

Anyway, I've now made seq-uniq faster.  This used to take 27 seconds,
and now takes 1.4s.

(let ((list (seq-map-indexed (lambda (_ i)
			       i)
			     (make-list 10000 nil))))
  (setq list (append list list))
  ;;(benchmark-run 10 (gnus-delete-duplicates list))
  (benchmark-run 10 (seq-uniq list))
  )
This bug report was last modified 3 years and 2 days ago.

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