alt Hacker NewsWe write quite a bit of BPF at work for the Parca-Agent project[1]. And we find that even C is sometimes too high level of a language paired with modern optimization techniques as the code you write often doesn’t come out that way the other and and we have to resort to weird hacks or write assembly directly to appease the verifier.
Apart from that, the usual qualms one might have about C are not really relevant in eBPF land, so I’ve actually found it the nicest experience writing C I’ve ever had, the verifier is just the price we have to pay.
Yeah I actually advocate for dropping to assembly quite a lot in BPF:
- portability isn't a concern
- BPF ASM syntax is quite readable
- it can often let you write simpler code by directly doing what the verifier needs instead of dancing around trying to make Clang do it for you.
I think the most exciting alternative BPF language would be one where the compiler interacts with the verifier. E.g. if the program included a logical proof of correctness that the verifier could check more efficiently than its limited builtin analysis.