[fuzzy@jason fuzzy]$ perl benchmark_test.pl 

normal var (t0)
===============
 4 wallclock secs ( 3.12 usr +  0.00 sys =  3.12 CPU) @ 641.03/s (n=2000)

reference (t1)
==============
 3 wallclock secs ( 3.50 usr +  0.01 sys =  3.51 CPU) @ 569.80/s (n=2000)

difference (t0, t1)
===================
 1 wallclock secs (-0.38 usr + -0.01 sys = -0.39 CPU)