ocamlpypy is a fast JIT compiler for Ocaml bytecode that uses PyPy metatracing JIT compiler.
It is currently much faster than ocamlrun, and faster than ocamlopt on some tests (!), but there is still a lot to improve.
pypy ~/apps/pypy/rpython/bin/rpython -Ojit bytecode.py
ocamlc foo.ml -o foo.byte
./bytecode-c foo.byte