Benchmark: running array, hash, softref, each for at least 10 CPU seconds...
     array: 11 wallclock secs (10.50 usr +  0.00 sys = 10.50 CPU) @ 32119.33/s (n=337253)
      hash: 11 wallclock secs (10.30 usr +  0.00 sys = 10.30 CPU) @ 22763.50/s (n=234464)
   softref: 10 wallclock secs (10.39 usr +  0.00 sys = 10.39 CPU) @ 17753.61/s (n=184460)

use Benchmark;

foreach (1..10) {
        $hash{$_}   = 'x';
        $array[$_]  = 'x';
        ${"var_$_"} = 'x';
}

sub hash    {   $hash{$_} = 'hash!'  foreach 1..10 }
sub array   {  $array[$_] = 'array!' foreach 1..10 }
sub softref { ${"var_$_"} = 'ref!'   foreach 1..10 }

timethese(-10, {
        hash    => \&hash,
        array   => \&array,
        softref => \&softref,
});