$ time ./rtoa-pgatram-fixed2 t1.txt t1.txt t1.txt t1.txt >f.tmp
read_input_files  : 15996000 items
read file time    :    0.349 secs
roman_to_dec time :    0.468 secs
total time        :    0.818 secs

real    0m0.824s
user    0m0.768s
sys     0m0.056s

# https://perlmonks.org/?node_id=11152168 max_workers => 21
$ time perl rtoa-pgatram-mce.pl t1.txt t1.txt t1.txt t1.txt >p.tmp
rtoa pgatram start
time 0.770 secs

real    0m0.799s
user    0m15.147s
sys     0m0.131s