Module jaccl 

Experimental: MLX’s JACCL backend, RDMA over Thunderbolt 5 (macOS 26.2+), behind the jaccl feature. It is unverified on Thunderbolt 5 hardware; its algorithms are tested on an emulated fabric.

RDMA must be enabled once per Mac in recoveryOS (rdma_ctl enable), and every pair of ranks cabled (the mesh) or every rank cabled to its neighbours (the ring). The group is described by MLX’s device file and started as MLX’s (mlx.launch --backend jaccl or --backend jaccl-ring); see Config::from_env. devices lists this Mac’s RDMA devices to check a setup.

Structs

Config

A JACCL group’s configuration, as MLX’s jaccl::Config.

Options

Options of init_with.

RdmaDevice

One of this Mac’s RDMA devices (a Thunderbolt port).

Enums

PortState

A port’s state.

Topology

The topology a configuration selects.

Functions

devices

This Mac’s RDMA devices (empty when RDMA is not enabled); an error when the system library cannot be loaded.

init_with

Connects this rank’s JACCL group (not made the default group).

is_available

Whether RDMA can run here: the system library loads and lists at least one device.

parse_devices

MLX’s device file: a JSON array with one entry per rank, each an array with one entry per peer: null (no cable; the rank itself), a device name, or a list of names (one per cable; the k-th cable of a pair is the k-th name on both sides).