[debbugs-tracker] bug#17448: closed ([PATCH] grep: retry DFA superset after matched with multiple lines by it)

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Your message dated Fri, 09 May 2014 14:52:58 -0700
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and subject line Re: bug#17448: [PATCH] grep: retry DFA superset after matched 
with multiple lines by it
has caused the debbugs.gnu.org bug report #17448,
regarding [PATCH] grep: retry DFA superset after matched with multiple lines by 
it
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17448: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17448
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--- Begin Message --- Subject: [PATCH] grep: retry DFA superset after matched with multiple lines by it Date: Fri, 09 May 2014 23:40:48 +0900

Currently, when matched with multiple lines by DFA superset, return to
KWset.  However, it won't be wrong probably, because if matches with
multiple lines by DFA superset, also matches with single line there with
high probability.  Further more, if return to KWset after matched with
multiple line by DFA superset, dfafast won't work effectively.

This patch changes to retry DFA superset immediately after matched with
multiple lines by it.

I confirmed the patch by following tests.

  $ yes abcdabc | head -50000000 >k
  $ env LC_ALL=C time -p src/grep '\(ab\)cd\1d' k

  before:
    real 3.48       user 3.41       sys 0.06

  after:
    real 2.14       user 2.07       sys 0.06

Norihiro

0001-grep-retry-DFA-superset-after-matched-with-multiple-.patch
Description: Text document

--- End Message ---

--- Begin Message --- Subject: Re: bug#17448: [PATCH] grep: retry DFA superset after matched with multiple lines by it Date: Fri, 09 May 2014 14:52:58 -0700 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 Thanks, I installed that, along with the attached patch which improves it slightly by avoiding a test of the returned value of memrchr in a context where memrchr cannot return NULL, plus I redid the while-control to make it a bit clearer when the loop terminates.

0001-grep-minor-improvements-to-retry-DFA-superset-patch.patch
Description: Text document

--- End Message ---