-j1:
real	7m53.195s
user	7m23.475s
sys	0m28.979s

-j4:
real	2m21.122s
user	8m21.439s
sys	0m35.498s

-j7:
real	1m58.140s
user	11m50.001s
sys	0m49.386s

-j8:
real	1m53.850s
user	12m49.398s
sys	0m52.690s

real	1m53.596s
user	12m48.977s
sys	0m52.809s

-j9:
real	1m54.790s
user	12m55.178s
sys	0m53.749s

-j12:
real	1m55.133s
user	12m59.961s
sys	0m54.652s