$ NUM_THREADS=6 ./llil5vec-tbb big1.txt big2.txt big3.txt >big-5vec.tmp
llil5vec-tbb (fixed string length=6) start
use TBB
use boost sort
get properties      time : 0.367148 secs
sort properties     time : 0.274697 secs
vector stable sort  time : 0.385357 secs
write stdout        time : 0.390569 secs
total               time : 1.4179 secs

$ diff big-5vec.tmp big-3vec.tmp