It's basically doing random access I/O (the slowest thing your computer can do) proportional to (large constant factor) * (num imports in program) * (length of PYTHONPATH).
When you can use it, a shebang of
can speed things up substantially.
Perl starts up an order of magnitude faster too (more like 3ms than 30ms). Ruby seems to have the same problem as Python.
It's about 60ms on my other laptop (Linux), and that's just at the threshold of noticeable and annoying.