Rate Without /o    With /o    With qr
Without /o 42725/s         --       -26%       -39%
With /o    57636/s        35%         --       -18%
With qr    70185/s        64%        22%         --

##</code><code>##

      Rate  2//  2/o  1//  1/o  1qr  2qr
2// 31.4/s   --  -0%  -0%  -1% -25% -26%
2/o 31.5/s   0%   --  -0%  -0% -25% -25%
1// 31.6/s   0%   0%   --  -0% -25% -25%
1/o 31.6/s   1%   0%   0%   -- -25% -25%
1qr 41.9/s  33%  33%  33%  33%   --  -1%
2qr 42.2/s  34%  34%  34%  34%   1%   --

##</code><code>##

Without /o:2200
With /o:2200
With qr:2200

##</code><code>##

#!/usr/bin/perl -w
use strict;

use Benchmark qw( cmpthese );

chomp( my @words = <DATA> );
push @words, map $_ x 100, @words;
for(  @words  ) {
    if(  s/ /0/g  ) {
        s/0/ /;
        $_= reverse $_;
    }
}
seek DATA, 0, 0;
push @words, grep chomp, <DATA>;
@words= ( @words ) x 100;

my $alpha = '[a-zA-Z]';
my $alnum = '[a-zA-Z0-9]';
my $qr= qr/^$alpha$alnum+$/;

print
   'Without /o:' => testsub(), $/,
   'With /o:'    => testsubo(), $/,
   'With qr:'    => testsubqr(), $/;

cmpthese( -3, {
   '1//' => \&testsub,
   '1/o' => \&testsubo,
   '1qr' => \&testsubqr,
   '2//' => \&testsub,
   '2/o' => \&testsubo,
   '2qr' => \&testsubqr,
});

sub testsub {
  my $count = 0;

  foreach (@words) {
    $count++ if(/^$alpha$alnum+$/);
  }
  return $count;
}

sub testsubo {
  my $count = 0;

  foreach (@words) {
    $count++ if(/^$alpha$alnum+$/o);
  }
  return $count;
}

sub testsubqr {
  my $count = 0;

  foreach (@words) {
    $count++ if $_ =~ $qr;
  }
  return $count;
}
__DATA__
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