E:\Perl\site\lib\My>type Filter.pm
#! perl -slw
package My::Filter;
use Filter::Simple;
use Benchmark::Timer;

our $t = Benchmark::Timer->new();

FILTER_ONLY
    regex => sub {
        $_ = "(?{{ \$My::Filter::t->start('$_$/') }})"
           . "(?:$_)"
           . "(?{{ \$My::Filter::t->stop('$_$/') }})";
    },
;

sub report{ return $t->report() }

return 1 if caller();

use strict;
use My::Filter;

my $stuff = 'abcdefghijklmnopqrstuvwxyz';
for (1..1000) {
        if ( $stuff =~ m[pqr] ) {
                $stuff =~ s/(\G(?:.{3})+?)(?<=...)(.)(.)/$1$3$2/g;
        }
        $_ = $stuff;
        my $OK = 1 if m[pqr];
}
print $stuff;

print '=' x 20, 'Timing of regexs in ', $0, '=' x 20;
print My::Filter::report();

##</code><code>##

E:\Perl\site\lib\My>perl Filter.pm
Subroutine report redefined at E:/Perl/site/lib/My/Filter.pm line 16.
abcdefghijklmnopqrstuvwxyz
====================Timing of regexs in Filter.pm====================
2000 trials of pqr
 (260.000ms total), 130us/trial

5000 trials of (\G(?:.{3})+?)(?<=...)(.)(.)
 (640.000ms total), 128us/trial


##</code><code>##

C:\test>perl -MMy::Filter -e"$s='abc'; print 'ok' if $s =~ m[b]; print My::Filter::report();"
ok1 trial of b
 (0s total)

C:\test>