Debating the value of XDP

Posted Dec 8, 2016 16:32 UTC (Thu) by Tara_Li (guest, #26706)
Parent article: Debating the value of XDP

As XDP programs gain functionality, they will need access to increasingly sophisticated information from the rest of the networking stack.

This looks like the root of the problem here - the fear of creeping featuritis. XDP looks to be intended for a very limited set of issues where the slowdown on processing the rest of the packets is made up for by getting rid of some fraction quickly, hopefully leaving more time for the rest of the packets to get handled more thoroughly. But, if XDP gains more and more functionality, and handles more and more of the packets, at some point it no longer is the "fast path", but becomes the default "slow" path, vs. the old default "even slower path" (which is now only "even slower" because XDP has taken on so much, it's taking as long as the old default did). And yet, each project thinks that its particular class of problem packets should be taken care of first, meaning that small patches to add this new tiny bit of functionality get submitted to add something they need, while gradually slowing down ALL of the packets taking the so-called "fast path". It sounds like a good idea, but can any developer actually say that they believe that if something like this is implemented, it won't develop creeping featuritis?