Benchmark for Vim regexp engine performance

README

Regular expressions and data from
http://lh3lh3.users.sourceforge.net/reb.shtml

Regular expressions benchmarked:
URI         ([a-zA-Z][a-zA-Z0-9]*)://([^ /]+)(/[^ ]*)?
Email       ([^ @]+)@([^ @]+)
Date        ([0-9][0-9]?)/([0-9][0-9]?)/([0-9][0-9]([0-9][0-9])?)
URI|Email   ([a-zA-Z][a-zA-Z0-9]*)://([^ /]+)(/[^ ]*)?|([^ @]+)@([^ @]+)
Word        .*SCSI-

Results (in seconds):
                         URI   Email    Date    Sum3   URI|Email    Word
re=1                   16.34   13.65    4.07   34.06       29.46    0.49
re=2                   92.03    9.75    4.47  106.25      105.39    5.22
Python 2.7.3            2.69    5.17    1.01    8.87        7.72    3.40
Perl 5.14.2             0.35    0.33    0.32    1.00        8.12    0.31
GNU egrep 2.10          0.21    0.16    0.56    0.93       10.86    0.03
(Five runs each, Vim 7.3.1010, 64-bit i7-2700K CPU @ 3.50GHz x 8.)

The Vim results were obtained with the bench.sh script.

Python, Perl, and egrep were timed in similar fashion using these invocations:

    perl script.pl 'pattern' </path/to/data/howto >/dev/null
    python script.py 'pattern' </path/to/data/howto >/dev/null
    egrep 'pattern' /path/to/data/howto >/dev/null

The data file "howto" (~38M) is available at
http://people.unipmn.it/manzini/lightweight/corpus/howto.bz2

bench.sh

#!/bin/bash
# Usage: ./bench.sh <engine> <script>
# where engine is (1|2)
#       script is (uri|email|date|uriemail|word)

VIM="/path/to/vim/src/vim"
DATA="/path/to/data/howto"

vimrc="vimrc-${1:-1}"
rescript="re-${2:-word}.vim"
cmd=( "${VIM}" -N -u "${vimrc}" -i NONE -n -e -s -S "${rescript}" +quit "${DATA}" )

echo "${cmd[@]}" >&2

tmpfile="/tmp/,,tmp.$$"
for i in {1..5}; do
	\time -f '%e' -ao "${tmpfile}" "${cmd[@]}" &>/dev/null
	echo -n . >&2
done
echo >&2

result=$( awk '{ sum += $1 } END { printf "%.2f", sum / 5 }' "${tmpfile}" )

rm -f "${tmpfile}"

echo "${result}"

re-date.vim

g/\%([0-9][0-9]\=\)\/\%([0-9][0-9]\=\)\/\%([0-9][0-9]\%([0-9][0-9]\)\=\)/p

re-email.vim

g/\%([^ @]\+\)@\%([^ @]\+\)/p

re-uri.vim

g/\%([a-zA-Z][a-zA-Z0-9]*\):\/\/\%([^ /]\+\)\%(\/[^ ]*\)\=/p

re-uriemail.vim

g/\%([a-zA-Z][a-zA-Z0-9]*\):\/\/\%([^ /]\+\)\%(\/[^ ]*\)\=\|\%([^ @]\+\)@\%([^ @]\+\)/p

re-word.vim

g/.*SCSI-/p

script.pl

#!/usr/bin/env perl
use strict;
use warnings;

my $reobj = qr/$ARGV[0]/;

while (<STDIN>) {
    print $_ if /$reobj/;
}

script.py

#!/usr/bin/env python
import re
import sys

reobj = re.compile(sys.argv[1])

for line in sys.stdin:
    if reobj.search(line):
        sys.stdout.write(line)

vimrc-1

if exists('&regexpengine')
  set regexpengine=1
endif

vimrc-2

if exists('&regexpengine')
  set regexpengine=2
endif