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> BPF is the extremely simple and limited virtual machine No longer true in modern Linux. http://www.brendangregg.com/blog/index.html http://www.brendangregg.
by cthalupa 11y ago
> BPF is the extremely simple and limited virtual machine
No longer true in modern Linux.
http://www.brendangregg.com/blog/index.html http://www.brendangregg.com/blog/index.html
- Dylan16807 11y agoYes it is. Going from 2 to 10 registers and getting map data structures and compilation to machine code doesn't change that BPF is intentionally simple and even disallows loops. "simple and limited" is a good thing.
- cthalupa 11y agoIt's simple, sure. And it's limited, in that there are sane limits in place, because you don't want an application running in the kernel to loop for forever, but 'extremely simple and limited' I don't think is fair. You can do a hell of a lot with BPF, and it's not like work to extend it's functionality is slowing down, either. We've had tons of features implemented in the 4.x family, stack walking is likely to be implemented in the future, etc. When you have people like Alexei Starovoitov and Brendan Gregg saying it can do all sorts of things including "crazy stuff", I think we've moved beyond 'extremely simple and limited'
- Dylan16807 11y agoYou're reading a negativity into that phrase that isn't really there. It's harshly limited, but in a careful way. Despite having few parts and not being turing complete it has a massive number of use cases.