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bug#43862: [PATCH] grep: set RE_NO_SUB for calling regex only to check s
From: |
Norihiro Tanaka |
Subject: |
bug#43862: [PATCH] grep: set RE_NO_SUB for calling regex only to check syntax |
Date: |
Thu, 08 Oct 2020 18:40:36 +0900 |
We can set RE_NO_SUB for calling regex only to check syntax. It brings
performance gains in cases to have a lot of enormous epsilon nodes.
$ printf '(%020000d)\n' | sed 's/0/|/g' >pat
(before)
$ time -p env LC_ALL=C src/grep -Ef pat /dev/null
real 6.15
user 4.62
sys 1.52
(after)
$ time -p env LC_ALL=C src/grep -Ef pat /dev/null
real 0.66
user 0.19
sys 0.46
0001-grep-set-RE_NO_SUB-for-calling-regex-only-to-check-s.patch
Description: Text document
- bug#43862: [PATCH] grep: set RE_NO_SUB for calling regex only to check syntax,
Norihiro Tanaka <=