Core Concepts

HORUS provides multiple IPC backends, each optimized for different use cases. All backends share the same API for seamless switching.

Architecture Overview

─────────────────────────────────────────
           HORUS Application             
─────────────────────────────────────────
      Publisher/Subscriber API           
─────────────────────────────────────────
     Link (SPSC)    Hub (MPMC)          
─────────────────────────────────────────
        Shared Memory (/dev/shm)         
─────────────────────────────────────────

Communication System

Hub (Topic-Based Pub/Sub)

Production-Grade Message Passing

• Latency: 296ns-2.8µs for production messages (with serde)
• Use case: All robotics applications - control, sensing, perception
• Message Types: CmdVel (296ns), IMU (718ns), LaserScan (1.31µs), Odometry (650ns)

use horus::prelude::*;
use horus_library::messages::CmdVel;

// Create publisher/subscriber for any message type
let mut cmd_pub: Hub<CmdVel> = Hub::new("motor/cmd_vel")?;
let mut cmd_sub: Hub<CmdVel> = Hub::new("motor/cmd_vel")?;

// Multiple publishers can send to same topic
let mut pub1: Hub<SensorData> = Hub::new("sensors/imu")?;
let mut pub2: Hub<SensorData> = Hub::new("sensors/imu")?;

// Multiple subscribers receive all messages
let mut sub1: Hub<SensorData> = Hub::new("sensors/imu")?;
let mut sub2: Hub<SensorData> = Hub::new("sensors/imu")?;

Production Performance

Real Message Latencies (with serde serialization):

See Benchmarks for complete performance analysis.

Efficient Shared Memory

HORUS uses shared memory for fast IPC:

1. Efficient serialization with serde + bincode
2. Shared memory ring buffers for message passing
3. Lock-free operations where possible
4. Fixed-size message structures for safety

use horus::prelude::*;

// Send complex message types
let cmd = CmdVel::new(1.5, 0.8);  // 296ns latency
pub.send(cmd, Some(&mut node))?;

if let Some(cmd) = sub.recv() {
    println!("Linear: {}, Angular: {}", cmd.linear, cmd.angular);
}

Message Safety

HORUS messages are memory-safe by design:

• Fixed-size arrays instead of Vec for shared memory
• #[repr(C)] for consistent memory layout
• Serde for safe serialization
• No heap allocation in hot paths

Next Steps

• Getting Started - Build your first HORUS node
• Benchmarks - Production performance analysis
• Examples - Real-world robotics applications