Crate hft_channel 

SPMC broadcast channel for HFT and real-time systems

A lightweight, ultra-low-latency single-producer / multi-consumer broadcast channel designed for high-frequency trading (HFT) and other real-time systems.

Provides predictable performance, minimal contention, and carefully controlled memory access patterns. Supports thread-to-thread broadcasting via local memory, or inter-process communication using shared memory.

Features

• Lock-free single-producer / multi-consumer broadcast channel
• Seq_no protocol for overwrite detection
• Spin-wait receivers for ultra-low latency
• Cache-friendly layout (CachePadded)
• Works between threads or between processes via shared memory
• Zero allocations after initialization
• no_std-friendly design

Spin-Wait Behavior

Receivers use busy-waiting (spin loops) to wait for the producer to complete publishing the next message.

Implications:

• Lowest possible latency (no OS scheduling)
• A receiver consumes one logical CPU core while waiting
• Best when producer and receivers are on the same NUMA node
• Not ideal when power efficiency is important
• No OS blocking (by design)

This design is intended for HFT, trading engines, matching engines, real-time telemetry, and other performance-critical workloads.

Quick Example

use hft_channel::spmc_broadcast::channel;

let (tx, rx) = channel::<u64>("/test", 512);

let (_, payload) = tx.reserve();
*payload = 42;
tx.commit();

let (_, payload) = rx.recv();

Design Overview

Each slot’s state is encoded as:

[ dirty (1 bit, MSB) | seq_no (63 bits) ]

Guarantees:

• At least one slot is always dirty
• Dirty slot = currently being written
• Clean slot = readable and stable
• If a receiver observes a changed seq_no, the slot was overwritten

Typical protocol:

1. Sender marks the next reserved slot dirty
2. Sender writes the payload into the current reserved slot
3. Sender clears the dirty flag (commit)
4. Receiver waits for dirty == false, then reads or copies the payload

Modules

spmc_broadcast

Structs

Trials

Functions

mono_time_ns

Returns timestamp in ns