use Time::HiRes qw(sleep time);

my $time = time;
for (1..1_000_000)
{
   my $str = '123456789';
   my ($a,$b) = $str =~  m/(23)[^8]+(8)/g; # about 1.88 sec
   #my ($a,$b) = $str =~  m/(23)[^8]+(8)/; # about 2.15 sec
   #my ($a) = $str =~  m/(23)/g;           # about 1.23 sec
   #my ($a) = $str =~  m/(23)/;            # about 1.41 sec
}
say time - $time;