build.sh

# Prime the Cache
$ time python setup.py build --build-base ~v/tmp-ec63b471f919101/cache/
...
python setup.py build --build-base ~v/tmp-ec63b471f919101/cache/  76.24s user 4.16s system 96% cpu 1:23.33 total

# Test in place rebuilds
$ time python setup.py build --build-base ~v/tmp-ec63b471f919101/cache/
...
python setup.py build --build-base ~v/tmp-ec63b471f919101/cache/  0.81s user 0.27s system 84% cpu 1.265 total

# Test sdist based rebuilds
$ time python setup.py sdist
...
python setup.py sdist  2.15s user 0.46s system 96% cpu 2.699 total
$ time tar zxvf numpy-1.14.0.dev0+c556b42.tar.gz
...
tar zxvf numpy-1.14.0.dev0+c556b42.tar.gz  0.07s user 0.16s system 88% cpu 0.254 total
$ time python setup.py build --build-base ~v/tmp-ec63b471f919101/cache/
...
python setup.py build --build-base ~v/tmp-ec63b471f919101/cache/  0.77s user 0.29s system 83% cpu 1.269 total