my $t1 = timeit(1_000_000, \&odd_1);
my $t2 = timeit(1_000_000, \&odd_2);
print "odd_1: ",timestr($t1),"\n";
print "odd_2: ",timestr($t2),"\n";

sub odd_1 {
  my $num = rand(2**31);
  return $num % 2;
}

sub odd_2 {
  my $num = rand(2**31);
  return $num & 1;
}

##</code><code>##

[falkkin@shadow ~/perl] perl odd.pl
odd_1:  6 wallclock secs ( 6.29 usr + -0.00 sys =  6.29 CPU) @ 158982.51/s (n=1000000)
odd_2: 10 wallclock secs ( 9.36 usr + -0.01 sys =  9.35 CPU) @ 106951.87/s (n=1000000)