GNU bug report logs - #22103
[PATCH] grep: improve performance for grep -P in UTF-8

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
To: <bug-grep <at> gnu.org>
Subject: [PATCH] grep: improve performance for grep -P in UTF-8
Date: Mon, 07 Dec 2015 08:01:23 +0900

[Message part 1 (text/plain, inline)]

After grep -P found first match, TEXTBIN_UNKNOWN optimizations is not
used.  Therefore, if grep -P found early match, grep -P is very slow in
UTF-8.

  $ time -p grep -P ^1$ <(seq 999999)
  1
  real 14.55
  user 13.77
  sys 1.12

Or grep -Pa is not used TEXTBIN_UNKNOWN optimizations.  Therefere, it is
also very slow in UTF-8.

grep -P ^1$ <(seq 999999)

  $ time -p grep -Pa a <(seq 999999)
  real 14.53
  user 13.65
  sys 1.35

This change makes deference to leave TEXTBIN_UNKNOWN optimizations until
grep -P finds a binary character.

It will bring more than 10x speed up.

  $ time -p src/grep -P ^1$ <(seq 999999)
  1
  real 0.97
  user 0.79
  sys 0.24

  $ time -p src/grep -Pa a <(seq 999999)
  real 0.98
  user 0.23
  sys 0.99

BTW, this change conflicts with proposal in bug#22028.

[0001-grep-improve-performance-for-grep-P-in-UTF-8.patch (text/plain, attachment)]

Message #10 received at 22103-done <at> debbugs.gnu.org (full text, mbox):

From: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
To: 22103-done <at> debbugs.gnu.org
Subject: Re: bug#20526: grep BUG: text file is detected as binary
Date: Fri, 08 Jan 2016 22:46:33 +0900

On Wed, 6 Jan 2016 09:57:46 -0800
Paul Eggert <eggert <at> cs.ucla.edu> wrote:

> On 01/06/2016 12:32 AM, Paul Eggert wrote:
> > I installed the attached patch, which fixed this performance bug for me. 
> Whoops! I forgot to 'git add src/search.h' before committing. We also need the attached followup patch, which I installed.

Great!   Thanks, many issues including for output of invalid sequence
are fixed by your patches.  bug#22103 is also fixed in them, so I am
closing it.

Message #13 received at 22103 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: 22103 <at> debbugs.gnu.org, Norihiro Tanaka <noritnk <at> kcn.ne.jp>
Cc: 22103-done <at> debbugs.gnu.org
Subject: Re: bug#22103: bug#20526: grep BUG: text file is detected as binary
Date: Fri, 8 Jan 2016 13:35:12 -0800

On Fri, Jan 8, 2016 at 5:46 AM, Norihiro Tanaka <noritnk <at> kcn.ne.jp> wrote:
>
> On Wed, 6 Jan 2016 09:57:46 -0800
> Paul Eggert <eggert <at> cs.ucla.edu> wrote:
>
>> On 01/06/2016 12:32 AM, Paul Eggert wrote:
>> > I installed the attached patch, which fixed this performance bug for me.
>> Whoops! I forgot to 'git add src/search.h' before committing. We also need the attached followup patch, which I installed.
>
> Great!   Thanks, many issues including for output of invalid sequence
> are fixed by your patches.  bug#22103 is also fixed in them, so I am
> closing it.

Thank you for helping with bug triage.

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