Clearly that particular regex isn't doing anything useful, but it ended up being the portion of another useful regex that was slowing things down. Here is the output of running the two Perls with the '-V' option if that might help explain things:[dmandel@midgard dmandel]# time perl -e '$x=join("",(a..z))x100; for (1..100){$x =~ s/(.*?)I/$1/isge;}' real 0m3.420s user 0m2.590s sys 0m0.000s [dmandel@midgard dmandel]# time perl5.6.1 -e '$x=join("",(a..z))x100; + for (1..100){$x =~ s/(.*?)I/$1/isge;}' real 0m0.151s user 0m0.050s sys 0m0.000s [dmandel@midgard dmandel]# time perl -e '$x=join("",(a..z))x100; for (1..100){$x =~ s/(.*?)I/$1/isge;}' real 0m2.584s user 0m2.580s sys 0m0.010s [dmandel@midgard dmandel]# time perl5.6.1 -e '$x=join("",(a..z))x100; + for (1..100){$x =~ s/(.*?)I/$1/isge;}' real 0m0.108s user 0m0.050s sys 0m0.000s [dmandel@midgard dmandel]# time perl -e '$x=join("",(a..z))x100; for (1..100){$x =~ s/(.*?)I/$1/isge;}' real 0m2.718s user 0m2.570s sys 0m0.010s [dmandel@midgard dmandel]# time perl5.6.1 -e '$x=join("",(a..z))x100; + for (1..100){$x =~ s/(.*?)I/$1/isge;}' real 0m0.047s user 0m0.050s sys 0m0.000s
and 5.6.1:[dmandel@midgard dmandel]# perl -V Summary of my perl5 (revision 5.0 version 8 subversion 2) configuratio +n: Platform: osname=linux, osvers=2.4.20-28.9, archname=i686-linux-thread-multi uname='linux midgard 2.4.20-28.9 #1 thu dec 18 13:45:22 est 2003 i +686 i686 i386 gnulinux ' config_args='' hint=recommended, useposix=true, d_sigaction=define usethreads=define use5005threads=undef useithreads=define usemulti +plicity=define useperlio=define d_sfio=undef uselargefiles=define usesocks=undef use64bitint=undef use64bitall=undef uselongdouble=undef usemymalloc=n, bincompat5005=undef Compiler: cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS +-fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE +_OFFSET_BITS=64 -I/usr/include/gdbm', optimize='-O3', cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -fno-stri +ct-aliasing -I/usr/local/include -I/usr/include/gdbm' ccversion='', gccversion='3.2.2 20030222 (Red Hat Linux 3.2.2-5)', + gccosandvers='' intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1 +2 ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', + lseeksize=8 alignbytes=4, prototype=define Linker and Libraries: ld='cc', ldflags =' -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc libc=/lib/libc-2.3.2.so, so=so, useshrplib=false, libperl=libperl. +a gnulibc_version='2.3.2' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynami +c' cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib' Characteristics of this binary (from libperl): Compile-time options: MULTIPLICITY USE_ITHREADS USE_LARGE_FILES PERL +_IMPLICIT_CONTEXT Built under linux Compiled at Jan 8 2004 21:52:16 @INC: /usr/local/lib/perl5/5.8.2/i686-linux-thread-multi /usr/local/lib/perl5/5.8.2 /usr/local/lib/perl5/site_perl/5.8.2/i686-linux-thread-multi /usr/local/lib/perl5/site_perl/5.8.2 /usr/local/lib/perl5/site_perl
[dmandel@midgard dmandel]# perl5.6.1 -V Summary of my perl5 (revision 5.0 version 6 subversion 1) configuratio +n: Platform: osname=linux, osvers=2.4.21-1.1931.2.393.entsmp, archname=i386-lin +ux uname='linux bugs.devel.redhat.com 2.4.21-1.1931.2.393.entsmp #1 s +mp thu aug 14 14:47:21 edt 2003 i686 unknown ' config_args='-des -Doptimize=-O2 -march=i386 -mcpu=i686 -Dcc=gcc - +Dcf_by=Red Hat, Inc. -Dcccdlflags=-fPIC -Dinstallprefix=/usr -Dprefix +=/usr -Darchname=i386-linux -Dvendorprefix=/usr -Dsiteprefix=/usr -Uu +sethreads -Uuseithreads -Uuselargefiles -Dd_dosuid -Dd_semctl_semun - +Di_db -Di_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Dinc_ver +sion_list=5.6.0/i386-linux 5.6.0' hint=recommended, useposix=true, d_sigaction=define usethreads=undef use5005threads=undef useithreads=undef usemultipl +icity=undef useperlio=undef d_sfio=undef uselargefiles=undef usesocks=undef use64bitint=undef use64bitall=undef uselongdouble=undef Compiler: cc='gcc', ccflags ='-fno-strict-aliasing -I/usr/local/include', optimize='-O2 -march=i386 -mcpu=i686', cppflags='-fno-strict-aliasing -I/usr/local/include' ccversion='', gccversion='2.96 20000731 (Red Hat Linux 7.3 2.96-11 +3)', gccosandvers='' intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1 +2 ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', + lseeksize=4 alignbytes=4, usemymalloc=n, prototype=define Linker and Libraries: ld='gcc', ldflags =' -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lnsl -ldl -lm -lc -lcrypt -lutil perllibs=-lnsl -ldl -lm -lc -lcrypt -lutil libc=/lib/libc-2.2.5.so, so=so, useshrplib=false, libperl=libperl. +a Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynami +c' cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib' Characteristics of this binary (from libperl): Compile-time options: Built under linux Compiled at Aug 18 2003 16:08:31 @INC: /usr/lib/perl5/5.6.1/i386-linux /usr/lib/perl5/5.6.1 /usr/lib/perl5/site_perl/5.6.1/i386-linux /usr/lib/perl5/site_perl/5.6.1 /usr/lib/perl5/site_perl/5.6.0/i386-linux /usr/lib/perl5/site_perl/5.6.0 /usr/lib/perl5/site_perl /usr/lib/perl5/vendor_perl/5.6.1/i386-linux /usr/lib/perl5/vendor_perl/5.6.1 /usr/lib/perl5/vendor_perl
Edited by Chady -- added readmore tag.
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