[$] Faster firewalls with bpfilter
From servers in a data center to desktop computers, many devices communicating on a network will eventually have to filter network traffic, whether it's for security or performance reasons. As a result, this is a domain where a lot of work is put into improving performance: a tiny performance improvement can have considerable gains. Bpfilter is a project that allows for packet filtering to easily be done with BPF, which can be faster than other mechanisms.