redo: 5.4s
redo -j4: 3.0s
make: 2.3s
make -j4: 1.4s
make SHELL=/bin/dash: 1.2s
make SHELL=/bin/dash -j4: 0.83s
We have some distance to go yet. Of course, redo is still written in
python, not C, so it's very expensive, and the on-disk dependency store is
very inefficient.
...because it seems my locking isn't very good. It exposes annoying
problems involving rebuilding the same files more than once, screwing up
stamp files with redo -j, and being unnecessarily slow when checking
dependencies. So it's a pretty good test considering how simple it is.
Didn't add it to t/all.do yet, because it would fail.
