GNU bug report logs - #15191
faster DFA.C state merge

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Package: grep;

Reported by: Ivan Yanikov <dobrokot <at> gmail.com>

Date: Mon, 26 Aug 2013 06:58:03 UTC

Severity: wishlist

Tags: moreinfo, patch

Done: Paul Eggert <eggert <at> cs.ucla.edu>

Bug is archived. No further changes may be made.

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From: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
To: 15191 <at> debbugs.gnu.org
Cc: Paul Eggert <eggert <at> cs.ucla.edu>, Ivan Yanikov <dobrokot <at> gmail.com>
Subject: bug#15191: faster DFA.C state merge
Date: Sat, 17 May 2014 11:03:13 +0900

[Message part 1 (text/plain, inline)]
I tried it on grep-2.14, and I confirmed that the patch is effective
certainly.  However, I see that it's fixed in bug#17377.

$ env LC_ALL=C time -p ../grep-2.19/src/grep -E -f regex.re input_lines.txt

grep-2.14
  before: real 7.66  user 7.56  sys 0.09
  after : real 2.06  user 1.96  sys 0.09

grep-2.18.146-ebf3
  before: real 1.59  user 1.50  sys 0.08
  after : real 1.99  user 1.86  sys 0.12

If my rewriting of the patch is right, it causes slowdown rather by
building heap.

Norihiro

[dfa_faster_state_merge.diff (text/plain, attachment)]
This bug report was last modified 11 years and 12 days ago.

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