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Postings from August 2008
[perl #58280] Speed lost on /^(foo|bar|baz)$/ match
From:
Michael G Schwern
Date:
August 23, 2008 04:21
Subject:
[perl #58280] Speed lost on /^(foo|bar|baz)$/ match
Message ID:
rt-3.6.HEAD-29759-1219444109-709.58280-75-0@perl.org
# New Ticket Created by Michael G Schwern
# Please include the string: [perl #58280]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=58280 >
This is a bug report for perl from schwern@pobox.com,
generated with the help of perlbug 1.39 running under perl 5.11.0.
-----------------------------------------------------------------
[Please describe your issue here]
I was testing out an efficiency claim and discovered that 5.10 and
bleadperl have both lost a lot of performance on /^(foo|bar|baz)$/
type regexes.
#!/usr/bin/perl -w
use strict;
use warnings;
use Benchmark qw(cmpthese);
my $token = "open";
cmpthese(shift || -3, {
regex => sub { $token =~ m/\A (?: open | close | read ) \z/xms; },
regex_opt => sub { $token =~ m/^(?:open|close|read)$/; },
eq => sub { $token eq 'open' ||
$token eq 'close' ||
$token eq 'read';
}
});
$ bleadperl ~/tmp/bug.plx 5000000
Rate regex_opt regex eq
regex_opt 1222494/s -- -5% -85%
regex 1282051/s 5% -- -84%
eq 8064516/s 560% 529% --
$ perl5.8.8 ~/tmp/bug.plx 5000000
Rate regex_opt regex eq
regex_opt 3048780/s -- -1% -54%
regex 3086420/s 1% -- -53%
eq 6578947/s 116% 113% --
$ perl5.10.0 ~/tmp/bug.plx 5000000
Rate regex regex_opt eq
regex 1492537/s -- -0% -89%
regex_opt 1497006/s 0% -- -89%
eq 13157895/s 782% 779% --
Can anyone duplicate?
[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
category=core
severity=low
---
Site configuration information for perl 5.11.0:
Configured by schwern at Fri Aug 22 15:15:47 PDT 2008.
Summary of my perl5 (revision 5 version 11 subversion 0 patch 34218) configuration:
Platform:
osname=darwin, osvers=8.11.1, archname=darwin-thread-multi-2level
uname='darwin windhund.schwern.org 8.11.1 darwin kernel version 8.11.1: wed oct 10 18:23:28 pdt 2007; root:xnu-792.25.20~1release_i386 i386 i386 macbook1,1 darwin '
config_args='-de -Dprefix=/usr/local/perl/blead -Dusedevel -Duseithreads -Dccflags=-I/sw/include -Dldflags=-L/sw/lib -Dperladmin=schwern@pobox.com -Dcf_email=schwern@pobox.com -Dmyhostname=windhund -Dmydomain=.schwern.org -Dlibpth=/usr/local/lib /sw/lib /opt/local/lib /usr/lib -Uversiononly -Uinstallusrbinperl'
hint=recommended, useposix=true, d_sigaction=define
useithreads=define, usemultiplicity=define
useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
use64bitint=undef, use64bitall=undef, uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='cc', ccflags ='-I/sw/include -fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -I/usr/local/include -I/opt/local/include',
optimize='-O3',
cppflags='-no-cpp-precomp -I/sw/include -fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -I/usr/local/include -I/opt/local/include'
ccversion='', gccversion='4.0.1 (Apple Computer, Inc. build 5370)', gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags ='-L/sw/lib -L/usr/local/lib -L/opt/local/lib'
libpth=/usr/local/lib /sw/lib /opt/local/lib /usr/lib
libs=-lgdbm -ldbm -ldb -ldl -lm -lc
perllibs=-ldl -lm -lc
libc=/usr/lib/libc.dylib, so=dylib, useshrplib=false, libperl=libperl.a
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
cccdlflags=' ', lddlflags='-L/sw/lib -bundle -undefined dynamic_lookup -L/usr/local/lib -L/opt/local/lib'
Locally applied patches:
DEVEL
---
@INC for perl 5.11.0:
/sw/lib/perl5/darwin-thread-multi-2level
/sw/lib/perl5
/sw/lib/perl5/darwin
/usr/local/perl/blead/lib/5.11.0/darwin-thread-multi-2level
/usr/local/perl/blead/lib/5.11.0
/usr/local/perl/blead/lib/site_perl/5.11.0/darwin-thread-multi-2level
/usr/local/perl/blead/lib/site_perl/5.11.0
/usr/local/perl/blead/lib/site_perl/5.10.0
/usr/local/perl/blead/lib/site_perl
.
---
Environment for perl 5.11.0:
DYLD_LIBRARY_PATH (unset)
HOME=/Users/schwern
LANG (unset)
LANGUAGE (unset)
LC_CTYPE=en_US.UTF-8
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/Users/schwern/bin:/usr/local/bin:/opt/local/bin:/opt/local/sbin:/sw/bin:/sw/sbin:/Users/schwern/bin:/usr/local/bin:/usr/local/bin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/X11R6/bin
PERL5LIB=/sw/lib/perl5:/sw/lib/perl5/darwin
PERL_BADLANG (unset)
SHELL=/bin/bash
-
[perl #58280] Speed lost on /^(foo|bar|baz)$/ match
by Michael G Schwern