On Sat, 29 Oct 2016 09:53:28 +0200, Jiri Pirko wrote: > Hi all. > > The network world is divided into 2 general types of hw: > 1) network ASICs - network specific silicon, containing things like TCAM > These ASICs are suitable to be programmed by P4. > 2) network processors - basically a general purpose CPUs > These processors are suitable to be programmed by eBPF. > > I believe that by now, the most people came to a conclusion that it is > very difficult to handle both types by either P4 or eBPF. And since > eBPF is part of the kernel, I would like to introduce P4 into kernel > as well. Here's a plan: > > 1) Define P4 intermediate representation > I cannot imagine loading P4 program (c-like syntax text file) into > kernel as is. That means that as the first step, we need find some > intermediate representation. I can imagine someting in a form of AST, > call it "p4ast". I don't really know how to do this exactly though, > it's just an idea. > > In the end there would be a userspace precompiler for this: > $ makep4ast example.p4 example.ast
Maybe stating the obvious, but IMHO defining the IR is the hardest part. eBPF *is* the IR, we can compile C, P4 or even JIT Lua to eBPF. The AST/IR for switch pipelines should allow for similar flexibility. Looser coupling would also protect us from changes in spec of the high level language.
