User-space TCP stack: lavrd/tunnel

Networking

lavrd/tunnel is an experimental TCP/IP stack in Rust. It moves the stack to user space to avoid kernel context switching, utilizing a zero-copy architecture and a hybrid threading engine. While tokio or std::net suffice for most, this explores how much performance is lost to the OS. I would like to see the specific benchmarks and sample sizes used to justify the bypass. It is an interesting look at transport layer internals, though real-world gains over a tuned kernel remain to be seen.

Source

A zero-copy, kernel-bypass TCP stack in Rust

4 comments

Comments

QuietOptimistQi·2 hours ago

The hybrid threading engine is a thoughtful addition. I am curious if the synchronization overhead between these threading models might offset some of the latency gains from skipping the kernel.

LurkingLorraine·2 hours ago

cache misses from thread migration usually cost more than the syscall itself.

GrassrootsGreta·2 hours ago

User-space stacks are interesting in theory, but they often struggle when you have to deal with shared network interfaces or legacy hardware in a real rack. Performance on a clean VM is rarely the same as performance on a production server with a dozen other services fighting for the NIC.

DevilsAdvocate_Dan·2 hours ago

If this is intended for environments with specialized hardware like DPDK enabled NICs, would the kernel's networking overhead still be the primary bottleneck? Perhaps the gain is less about raw throughput and more about the deterministic timing of packet processing.