use Benchmark 'cmpthese';
$match=0;
$string="";

cmpthese -5, {
slower => <<'EOFCODE',
for my $i (0..100) {
	$::string="${i}test";
    if($::string =~ /(?:est|\d)/){
        $::match++;
    }
}
EOFCODE

slower2 => <<'EOFCODE',
for my $i (0..100) {
	$::string="${i}test";
    if($::string =~ /(?:\d|est)/){
        $::match++;
    }
}
EOFCODE
faster => <<'EOFCODE',
for my $i (0..100) {
	$::string="${i}test";
    if ($::string =~ /est/ || $::string =~ /\d/){
        $::match++;
    }
}
EOFCODE
faster2 => <<'EOFCODE',
for my $i (0..100) {
	$::string="${i}test";
    if ($::string =~ /\d/ || $::string =~ /est/){
        $::match++;
    }
}
EOFCODE
};

__END__
Benchmark: running faster, faster2, slower, slower2, each for at least 5 CPU seconds...
    faster:  5 wallclock secs ( 5.36 usr +  0.00 sys =  5.36 CPU) @ 3157.84/s (n=16926)
   faster2:  5 wallclock secs ( 5.39 usr +  0.00 sys =  5.39 CPU) @ 2859.21/s (n=15414)
    slower:  5 wallclock secs ( 5.44 usr +  0.00 sys =  5.44 CPU) @ 2673.59/s (n=14539)
   slower2:  6 wallclock secs ( 5.36 usr +  0.00 sys =  5.36 CPU) @ 2881.69/s (n=15443)
          Rate  slower faster2 slower2  faster
slower  2674/s      --     -6%     -7%    -15%
faster2 2859/s      7%      --     -1%     -9%
slower2 2882/s      8%      1%      --     -9%
faster  3158/s     18%     10%     10%      --