> P4 is a programming language for controlling packet forwarding planes in networking devices, such as routers and switches. In contrast to a general purpose language such as C or Python, P4 is a domain-specific language with a number of constructs optimized for network data forwarding. P4 is distributed as open-source, permissively licensed code, and is maintained by the P4 Project (formerly the P4 Language Consortium), a not-for-profit organization hosted by the Open Networking Foundation.
But should (browser) WASM processes cross the kernel boundary for BPF performance?
FWIW EVM/eWASM opcodes have a cost in gas/particles.
BPF instructions could also each have an abstract relative cost with or without real value.
BPF in WASM (unfortunately without the kernel performance advantages or possible side channels) or the fwiu now-defunct eWASM might be an easier place to test the value of costed opcodes.
The [e]BPF verifier does not yet rewrite according to opcode costs of candidate programs.
"A look inside the BPF verifier [lwn]" https://news.ycombinator.com/item?id=41135478