with that code

sub ikei {
  my ($n, $m) = @_;
  use integer;
  my $q = $n / $m;
  my $r = $n % $m;
  return ($q+1) x $r, ($q) x ($m-$r);
}
[download]

       Rate  ike ikei
ike  50.8/s   --  -4%
ikei 52.8/s   4%   --

       Rate  ike ikei
ike  50.5/s   --  -5%
ikei 52.9/s   5%   --
[download]