MessagePack is an efficient binary serialization format. It lets you exchange data among multiple languages like JSON. But it's faster and smaller. Small integers are encoded into a single byte, and typical short strings require only one extra byte in addition to the strings themselves.
docker pull akalend/hhvm-msgpack docker run -it --name hhvm akalend/hhvm-msgpack /bin/bash
The attach to container:
docker exec -it hhvm /bin/bash