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by shanemhansen 315 days ago
You are right but it's confusing because there are two different approaches. I guess you could say both approaches improve performance by eliminating context switches and system calls.

1. Kernel bypass combined with DMA and techniques like dedicating a CPU to packet processing improve performance.

2. What I think of as "removing userspace from the data plane" improves performance for things like sendfile and ktls.

To your point, Quic in the kernel seems to not have either advantage.

1 comments

So... RDMA?
No, the first technique describes the basic way they already operate, DMA, but giving access to userspace directly because it's a zerocopy buffer. This is handled by the OS.

RDMA is directly from bus-to-bus, bypassing all the software.