$ time NUM_THREADS=1 ./rtoa-pgatram-openmp t1.txt t1.txt t1.txt t1.txt >s.tmp
use OpenMP
read_input_files  : 15996000 items
read file time    :    0.700 secs
roman_to_dec time :    0.556 secs
total time        :    1.256 secs

real    0m1.278s
user    0m0.928s
sys     0m0.350s