subetha

Cross-Context Channel (CXC) for Rust. Kernel-bypass IPC - lock-free, thread- and process-safe - that spans threads, processes, disk, and network through memory-mapped files, with no syscalls on the data path and no locks in your code.

Local IPC normally means picking the least-bad option from a menu that all goes through the kernel. SubEtha skips the menu: after construction, every send and recv is a user-space atomic op on a memory-mapped file the kernel page-aliases between participants. The same typed Channel<T> API works cross-thread, cross-process, and persisted to disk; the default ring picks and changes its own shape (SPSC to MPMC and back) under live producers and consumers without losing an item.

Measured 80-528x faster than the fastest kernel IPC mechanism on every platform tested (Windows, WSL2, Linux, FreeBSD, macOS) and 4.8-8.8x faster than iceoryx2's zero-copy shared memory. The full benchmark set, dot plots, and methodology live in the GitHub README.

This crate

subetha is the umbrella. It pulls in the whole stack and re-exports each member as a module:

Module	Crate	Role
`subetha::core`	`subetha-core`	shared substrate: handshake header, observation ring, `AxisMask`
`subetha::pointers`	`subetha-pointers`	adaptive in-process exotic pointers
`subetha::sidecar`	`subetha-sidecar`	adaptive control plane
`subetha::cxc`	`subetha-cxc`	MMF-backed cross-process primitives + bridges

[dependencies]
subetha = "0.1"

use subetha::cxc::AutoIpc;

let chan = AutoIpc::new("/tmp/events.bin")
    .capacity(64)
    .build_channel::<u64>()?;

chan.send(&42)?;                  // non-blocking
let v = chan.recv()?;
# Ok::<(), Box<dyn std::error::Error>>(())

Feature flags

The default build is dependency-light and cross-platform. The capability features forward to subetha-cxc; the platform- or C-library-specific dependencies behind each one stay gated, so the default build pulls none of them.

Feature	Adds
`quic-bridge`	`QuicBridgeClient` / `QuicBridgeServer` over QUIC (quinn + rustls)
`tcp-bridge`	`TcpBridgeClient` / `TcpBridgeServer` over TCP
`tcp-tls-bridge`	the TCP bridge inside a rustls 1.3 record layer
`tls`	the optional TLS record layer for the reliable-UDP transport
`wire-locale`	the NIC-bypass datapath (AF_XDP / netmap / BPF / XDP)
`linux-futex-raw`	the raw Linux futex surface on `CrossProcessWaker`

Requirements

SubEtha builds on stable Rust (edition 2024, MSRV 1.96).

Documentation

Full reference at the wiki: https://variably-constant.github.io/SubEtha/.

License