I suppose, the whole meaning of this example is to show how
to programm efficiently - not wasting system ressources (here: CPU time).
If this is so, I'd like to put emphasis on the fact, that NO ONE here seems to see a problem in the "true" expression. Please do not use interpolation if you do not need it. Try your benchmarks with 'true' again.
Of course I did the benchmarks before posting this node. The speed differences are not extraordinary but constantly about 5%
Code:
#!/usr/bin/perl_parallel -w
# For Emacs: -*- mode:cperl; mode:folding -*-
use strict;
use warnings;
use Benchmark;
my $value = "somewhere here true is there!";
timethese
(
5000000,
{
'index' => sub { index( $value, 'true' ) },
'regex' => sub { $value =~ /true/ },
}
);
timethese
(
5000000,
{
'index' => sub { index( lc $value, 'true' ) },
'regex' => sub { $value =~ /true/i },
}
);
Benchmark Results (single quotes):
Benchmark: timing 5000000 iterations of index, regex...
index: 2 wallclock secs ( 1.04 usr + 0.00 sys = 1.04 CPU) @ 48
+07692.31/s (n=5000000)
regex: 2 wallclock secs ( 2.16 usr + 0.01 sys = 2.17 CPU) @ 23
+04147.47/s (n=5000000)
Benchmark: timing 5000000 iterations of index, regex...
index: 3 wallclock secs ( 2.83 usr + 0.00 sys = 2.83 CPU) @ 17
+66784.45/s (n=5000000)
regex: 4 wallclock secs ( 3.45 usr + 0.02 sys = 3.47 CPU) @ 14
+40922.19/s (n=5000000)
Benchmark Results (double quotes):
Benchmark: timing 5000000 iterations of index, regex...
index: 1 wallclock secs ( 1.10 usr + 0.00 sys = 1.10 CPU) @ 45
+45454.55/s (n=5000000)
regex: 2 wallclock secs ( 2.25 usr + 0.01 sys = 2.26 CPU) @ 22
+12389.38/s (n=5000000)
Benchmark: timing 5000000 iterations of index, regex...
index: 4 wallclock secs ( 2.99 usr + 0.01 sys = 3.00 CPU) @ 16
+66666.67/s (n=5000000)
regex: 3 wallclock secs ( 3.66 usr + 0.01 sys = 3.67 CPU) @ 13
+62397.82/s (n=5000000)
Perl:
perl_parallel -V
Summary of my perl5 (revision 5 version 8 subversion 6) configuration:
Platform:
osname=linux, osvers=2.6.8-24-smp, archname=i586-linux-thread-mult
+i
uname='linux builder 2.6.8-24-smp #1 smp wed oct 6 09:16:23 utc 20
+04 i686 i686 i386 gnulinux '
config_args='-ds -e -Dprefix=/opt/PM_perl-5.8.6 -Dvendorprefix=/op
+t/PM_perl-5.8.6 -Dinstallusrbinperl -Dusethreads -Di_db -Di_dbm -Di_n
+dbm -Di_gdbm -Duseshrplib=true -Doptimize=-O2 -g -march=i586 -mcpu=i6
+86 -fmessage-length=0 -Wall -pipe'