llmq - low latency message queue

A multiprocess message queue designed to work without any work required in the kernel

high level architecture

Client libraries use llmq in a publisher/subscriber manner.

When a pubsub is initialized, it connects to the broker over a control socket. The broker establishes rx and tx ringbuffers over shared memory, hereafter called the dataplane.

The broker itself runs as a seperate process that constantly reads messages from the client publishers, and appropriately copies them to client subscribers

project structure

• /src/adapter

  Uses the frame decoder/encoder pattern to allow creating Sinks and Streams of arbitrary types on top of async Unix sockets

• /src/broker

  Handles control plane requests from clients, as well as runs data plane hotloop

• /src/protocol

  Actual types that are encoded and decoded using the adapter, so that clients and broker can communicate over the control plane.

• /src/queue

  Fast ringbuffer implementation on top of Unix shared memory. Allows for multiprocess queues with no locks and no kernel synchronization primitives.

• pubsub

  Actual library implementation that most clients should use