use strict;
use warnings;
use feature 'say';
use Benchmark 'cmpthese';

my $pat = qr/\d+/;
my $s = '123abc' x 1e6;

cmpthese -1, {
    foo => sub { 1 while $s =~ /\G $pat \D+ /cgx },
    bar => sub { 1 while $s =~ /\G $pat \D+ /cgxo },
};

__END__

          Rate  foo  bar
foo  1213522/s   -- -88%
bar 10345112/s 752%   --