$ perl chdir_benchmar
Benchmark: timing 1000 iterations of with_chdir, without_chdir...
with_chdir: 16 wallclock secs ( 8.11 usr +  8.46 sys = 16.57 CPU)
  @ 60.35/s (n=1000)
without_chdir: 31 wallclock secs (10.98 usr + 19.15 sys = 30.13 CPU)
  @ 33.19/s (n=1000)