$ time perl -w
use strict;
my $UPPER = 1_000_000;
my $sieve = "";
GUESS: for (my $guess = 2; $guess <= $UPPER; $guess++) {
  next GUESS if vec($sieve,$guess,1);
  #print "$guess\n";
  for (my $mults = $guess * $guess; $mults <= $UPPER; $mults += $guess) {
    vec($sieve,$mults,1) = 1;
  }
}
__END__

real    0m10.003s
user    0m2.191s
sys     0m0.003s