GNU bug report logs - #51231
increase performance and usability of binary search with -P

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

From: Carlo Arenas <carenas <at> gmail.com>
To: bug-grep <at> gnu.org
Subject: increase performance and usability of binary search with -P
Date: Fri, 15 Oct 2021 17:33:59 -0700

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

The following patch increase performance of grep when looking at
binary data, without any side effects:

Summary
  'cd grep; ./src/grep -Pc foo
/Users/carlo/Downloads/FreeBSD-13.0-BETA2-amd64.vhd' ran
    1.77 ± 0.02 times faster than 'cd grep.base; ./src/grep -Pc foo
/Users/carlo/Downloads/FreeBSD-13.0-BETA2-amd64.vhd'

Carlo

[0001-pcre-only-match-UTF-8-if-needle-is-UTF-8-and-case-fo.patch (application/octet-stream, attachment)]

Message #8 received at 51231 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Carlo Arenas <carenas <at> gmail.com>
Cc: 51231 <at> debbugs.gnu.org
Subject: Re: bug#51231: increase performance and usability of binary search
 with -P
Date: Fri, 15 Oct 2021 19:27:03 -0700

An all-ASCII pattern can match non-ASCII data. For example, the pattern 
'a.b' can match the string 'aΓb'. So it's not clear to me that the patch 
is correct in general.

For speed, try setting LC_ALL='C'.

Message #11 received at 51231 <at> debbugs.gnu.org (full text, mbox):

From: Carlo Arenas <carenas <at> gmail.com>
To: 51231 <at> debbugs.gnu.org
Subject: disregard patch
Date: Fri, 15 Oct 2021 18:59:49 -0700

And of course it has side effects (as shown by the test suite), and
would only help (if fixed) when the needle is a fixed string, which is
3x slower than doing -F, -G or -E.

Apologies for the distraction.

Carlo

Message #16 received at 51231-done <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Carlo Arenas <carenas <at> gmail.com>
Cc: 51231-done <at> debbugs.gnu.org
Subject: Re: bug#51231: disregard patch
Date: Sat, 16 Oct 2021 09:44:02 -0700

tags 51231 notabug
stop

On Sat, Oct 16, 2021 at 12:29 AM Carlo Arenas <carenas <at> gmail.com> wrote:
> And of course it has side effects (as shown by the test suite), and
> would only help (if fixed) when the needle is a fixed string, which is
> 3x slower than doing -F, -G or -E.
>
> Apologies for the distraction.

Marking this as "notabug" via first lines above and (via the "-done"
in recipient of 51231-done <at> debbugs.gnu.org) closing the issue.

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