use Benchmark;
timethese(100000, {
'Test' => 'eval{die "x" x 100000 if $] < 5.01}',
});

##</code><code>##

Benchmark: timing 100000 iterations of Test...
      Test: 15 wallclock secs (14.98 usr +  0.00 sys = 14.98 CPU) @ 6673.34/s (n=100000))

##</code><code>##

Benchmark: timing 100000 iterations of Test...
      Test:  0 wallclock secs ( 0.02 usr +  0.00 sys =  0.02 CPU) @ 6250000.00/ (n=100000)
            (warning: too few iterations for a reliable count)