$ sudo bash -c "echo 1 >/proc/sys/vm/drop_caches"
$ time wc lesms10_big.txt 
 14152200 113528600 652751200 lesms10_big.txt

real 0m3.412s
user 0m3.307s
sys  0m0.097s

$ sudo bash -c "echo 1 >/proc/sys/vm/drop_caches"
$ time ./wc.pl --max-workers=1 lesms10_big.txt
 14152200 113528600 652751200 lesms10_big.txt

real 0m3.553s
user 0m3.363s
sys  0m0.329s

$ sudo bash -c "echo 1 >/proc/sys/vm/drop_caches"
$ time ./wc.pl --max-workers=2 lesms10_big.txt
 14152200 113528600 652751200 lesms10_big.txt

real 0m1.804s
user 0m3.339s
sys  0m0.357s