brynhild:bash# ./test.sh 
make -j2 tests

real    1m42.418s
user    3m7.810s
sys     0m13.690s

real    1m20.462s
user    2m26.910s
sys     0m13.500s
-----
make -j4 tests

real    1m42.615s
user    3m9.100s
sys     0m13.600s

real    1m20.959s
user    2m30.550s
sys     0m10.620s
-----
-----
make -j6 tests

real    1m43.072s
user    3m10.020s
sys     0m13.380s

real    1m21.147s
user    2m31.040s
sys     0m10.410s
-----