BPF: A New Type of Software

Post by winternett » Thu, Dec 05, 2019, 7:45 PM UTC

pjmlp wrote: post #5

Android also uses it a lot. https://source.android.com/devices/architecture/kernel/bpf https://android.googlesource.com/platform/external/adeb/+/ma... https://linuxplumbersconf.org/event/4/contributions/411/atta... https://blog.linuxplumbersconf.org/2017/ocw/system/presentat...

Is this why Google is possibly de-prioritizing non-AMP sites on it's search index, making non-AMP sites load slowly on Google Chrome, Lobbying against Net Neutrality, and doing many other things like implementing flagging for sites in Chrome that aren't encrypted?

If that was ever a possibility then it would explain a lot... But that's none of my business...

Not making any officially accusatory statements here though mind you. ಠ_ಠ

Post by cube2222 » Fri, Dec 06, 2019, 7:39 PM UTC

nwallin wrote: post #128

throwaway894345 wrote: post #116

Earlier quoted context omitted.

According to https://news.ycombinator.com/item?id=18496054 , these programs have to halt? How does this system guarantee that the programs halt? Does this mean eBPF is not Turing complete?

The language itself is Turing complete, but the kernel will refuse to run a program that it cannot prove will halt. There are three categories of programs; programs you can trivially prove will halt, programs you can trivially prove won't halt, and programs where it's difficult or impossible to prove whether or not will halt. The third category is what we call the halting problem. Only the first category will be run…

This does actually mean that eBPF is not Turing complete, in that it can't simulate a Turing machine.

With a fixed number iterations (which also means fixed amount of memory) it's really just a finite state automata.

Re: BPF: A New Type of Software

Re: BPF: A New Type of Software