With a simple _oasis file (one library, no dependencies and one module), the result is the following (respectively with ```compiled_setup_ml``` and without):
```
$ time make 
./setup.exe -build
Finished, 0 targets (0 cached) in 00:00:00.
Finished, 6 targets (5 cached) in 00:00:00.
make  0.24s user 0.02s system 88% cpu 0.293 total

$ time make
ocaml setup.ml -build 
Finished, 0 targets (0 cached) in 00:00:00.
Finished, 6 targets (5 cached) in 00:00:00.
make  2.01s user 0.05s system 98% cpu 2.096 total
```