[debbugs-tracker] bug#24161: closed ([PATCH 2/2] sed: speed up matching by reguler expression with dfa matcher)

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Your message dated Mon, 8 Aug 2016 17:53:04 -0700
with message-id <address@hidden>
and subject line Re: bug#24161: [PATCH 2/2] sed: speed up matching by reguler 
expression with dfa matcher
has caused the debbugs.gnu.org bug report #24161,
regarding [PATCH 2/2] sed: speed up matching by reguler expression with dfa 
matcher
to be marked as done.

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24161: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=24161
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--- Begin Message --- Subject: [PATCH 2/2] sed: speed up matching by reguler expression with dfa matcher Date: Fri, 05 Aug 2016 23:03:26 +0900

Hi,

We can speeds up sed by using dfa matcher brought from grep.  gawk users
it, sed does not uses it yet.  It will speed up matching for typical
cases.

$ yes $(printf %040d 0) | head -1000000 >k

Before:

]$ time -p env LC_ALL=C sed/sed -ne /000000000k/p k
real 3.04
user 2.99
sys 0.03
$ time -p env LC_ALL=en_US.utf8 sed/sed -ne /000000000k/p k
real 3.04
user 2.90
sys 0.06
$ time -p env LC_ALL=ja_JP.eucjp sed/sed -ne /000000000k/p k
real 7.09
user 6.77
sys 0.31

After patching:

$ time -p env LC_ALL=C sed/sed -ne /000000000k/p k
real 0.29
user 0.15
sys 0.10
$ time -p env LC_ALL=en_US.utf8 sed/sed -ne /000000000k/p k
real 0.27
user 0.25
sys 0.02
$ time -p env LC_ALL=ja_JP.eucjp sed/sed -ne /000000000k/p k
real 0.33
user 0.29
sys 0.03

I believe that this patch can greatly improve performance of matching by
sed, however I worry about the maintenance as updates for dfa is always
done in grep.

Thanks,
Norihiro

0002-sed-speed-up-matching-by-reguler-expression-with-dfa.patch
Description: Text document

--- End Message ---

> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#24161: [PATCH 2/2] sed: speed up matching by reguler expression with dfa matcher
>
>
>
>
> Date: 
>
> Mon, 8 Aug 2016 17:53:04 -0700
>
>
>
>
> On Mon, Aug 8, 2016 at 4:29 PM, Norihiro Tanaka <address@hidden> wrote:
> >
> > On Sat, 6 Aug 2016 19:20:22 -0700
> > Jim Meyering <address@hidden> wrote:
> >
> >> Thanks again.
> >> I've revised it as follows and expect to push tomorrow:
> >>   - remove the abort and comment from dfaerror -- should is not
> >> necessary, given the _Noreturn attribute.
> >>   - adjusted commit log and NEWS entry, also moving the "Improvements"
> >> section to the top
> >>   - sorted source file names in local.mk (they were not sorted before, 
> >> either)
> >>   - added the "make syntax-check"-required mention of sed/dfa.c in
> >> po/POTFILES.in
> >
> > Thanks for adjusting.  I agree the all changes.
>
> Pushed.
>
>
> --- End Message ---