395 lines
12 KiB
Markdown
395 lines
12 KiB
Markdown
# agentic-robotics-rt
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[](https://crates.io/crates/agentic-robotics-rt)
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[](https://docs.rs/agentic-robotics-rt)
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[](../../LICENSE)
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**Real-time executor with priority scheduling for Agentic Robotics**
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Part of the [Agentic Robotics](https://github.com/ruvnet/vibecast) framework - high-performance robotics middleware with ROS2 compatibility.
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## Features
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- ⏱️ **Deterministic scheduling**: Priority-based task execution with deadlines
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- 🔄 **Dual runtime architecture**: Separate thread pools for high/low priority tasks
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- 📊 **Latency tracking**: HDR histogram for microsecond-precision measurements
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- 🎯 **Priority isolation**: High-priority tasks never blocked by low-priority work
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- ⚡ **Microsecond deadlines**: Schedule tasks with < 1ms deadlines
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- 🦀 **Rust async/await**: Full integration with Tokio ecosystem
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## Installation
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Add to your `Cargo.toml`:
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```toml
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[dependencies]
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agentic-robotics-core = "0.1.0"
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agentic-robotics-rt = "0.1.0"
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tokio = { version = "1", features = ["full"] }
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```
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## Quick Start
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### Basic Priority Scheduling
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```rust
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use agentic_robotics_rt::{Executor, Priority, Deadline};
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use std::time::Duration;
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#[tokio::main]
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async fn main() -> anyhow::Result<()> {
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// Create executor with dual runtime
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let executor = Executor::new()?;
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// High-priority 1kHz control loop
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executor.spawn_rt(
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Priority::High,
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Deadline::from_hz(1000), // 1ms deadline
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async {
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loop {
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// Read sensors, compute control, write actuators
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control_robot().await;
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tokio::time::sleep(Duration::from_micros(1000)).await;
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}
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}
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)?;
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// Low-priority logging (won't interfere with control loop)
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executor.spawn_rt(
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Priority::Low,
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Deadline::from_hz(10), // 100ms deadline
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async {
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loop {
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log_telemetry().await;
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tokio::time::sleep(Duration::from_millis(100)).await;
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}
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}
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)?;
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executor.run().await?;
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Ok(())
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}
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```
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### Deadline Enforcement
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```rust
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use agentic_robotics_rt::{Executor, Priority, Deadline};
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use std::time::Duration;
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let executor = Executor::new()?;
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// Critical task must complete within 500µs
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executor.spawn_rt(
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Priority::High,
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Deadline(Duration::from_micros(500)),
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async {
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// If this takes longer than 500µs, deadline missed warning
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critical_computation().await;
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}
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)?;
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```
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### Latency Monitoring
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```rust
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use agentic_robotics_rt::LatencyTracker;
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let tracker = LatencyTracker::new();
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let start = std::time::Instant::now();
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process_message().await;
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tracker.record(start.elapsed());
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// Get statistics
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println!("p50: {} µs", tracker.percentile(0.50) / 1000);
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println!("p95: {} µs", tracker.percentile(0.95) / 1000);
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println!("p99: {} µs", tracker.percentile(0.99) / 1000);
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println!("p99.9: {} µs", tracker.percentile(0.999) / 1000);
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```
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## Architecture
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```
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┌────────────────────────────────────────────┐
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│ agentic-robotics-rt (Executor) │
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├────────────────────────────────────────────┤
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│ │
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│ ┌──────────────────────────────────────┐ │
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│ │ Task Scheduler │ │
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│ │ • Priority queue │ │
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│ │ • Deadline tracking │ │
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│ │ • Work stealing │ │
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│ └──────────────────────────────────────┘ │
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│ │ │
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│ ┌─────────┴─────────┐ │
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│ │ │ │
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│ ┌───▼──────┐ ┌──────▼───┐ │
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│ │ High-Pri │ │ Low-Pri │ │
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│ │ Runtime │ │ Runtime │ │
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│ │ (2 thr) │ │ (4 thr) │ │
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│ └──────────┘ └──────────┘ │
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│ │ │ │
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│ ┌───▼───────────────────▼───┐ │
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│ │ Tokio Async Runtime │ │
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│ └────────────────────────────┘ │
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│ │
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└────────────────────────────────────────────┘
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```
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## Priority Levels
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The executor supports multiple priority levels:
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```rust
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pub enum Priority {
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Critical, // Real-time critical (< 100µs deadlines)
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High, // High priority (< 1ms deadlines)
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Medium, // Medium priority (< 10ms deadlines)
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Low, // Low priority (> 10ms deadlines)
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Background,// Background tasks (no deadline)
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}
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```
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### Priority Assignment Guidelines
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| Priority | Use Case | Example | Deadline |
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|----------|----------|---------|----------|
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| **Critical** | Safety-critical control | Emergency stop, collision avoidance | < 100 µs |
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| **High** | Real-time control | PID control, motor commands | < 1 ms |
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| **Medium** | Sensor processing | Image processing, point cloud filtering | < 10 ms |
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| **Low** | Perception | Object detection, SLAM | < 100 ms |
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| **Background** | Logging, telemetry | File I/O, network sync | No deadline |
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## Deadline Specification
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Multiple ways to specify deadlines:
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```rust
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use std::time::Duration;
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use agentic_robotics_rt::Deadline;
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// Direct duration
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let d1 = Deadline(Duration::from_micros(500));
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// From frequency (Hz)
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let d2 = Deadline::from_hz(1000); // 1 kHz = 1ms deadline
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// From milliseconds
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let d3 = Deadline::from_millis(10);
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// From microseconds
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let d4 = Deadline::from_micros(100);
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```
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## Real-Time Control Example
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```rust
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use agentic_robotics_core::Node;
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use agentic_robotics_rt::{Executor, Priority, Deadline};
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use std::time::Duration;
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#[tokio::main]
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async fn main() -> anyhow::Result<()> {
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let mut node = Node::new("robot_controller")?;
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let executor = Executor::new()?;
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// Subscribe to sensor data
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let sensor_sub = node.subscribe::<JointState>("/joint_states")?;
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// Publish control commands
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let cmd_pub = node.publish::<JointCommand>("/joint_commands")?;
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// High-priority 1kHz control loop
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executor.spawn_rt(
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Priority::High,
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Deadline::from_hz(1000),
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async move {
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loop {
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// Read latest sensor data (non-blocking)
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if let Some(state) = sensor_sub.try_recv() {
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// Compute control law
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let cmd = compute_control(&state);
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// Send command
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cmd_pub.publish(&cmd).await.ok();
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}
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// 1kHz loop
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tokio::time::sleep(Duration::from_micros(1000)).await;
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}
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}
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)?;
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// Low-priority telemetry
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executor.spawn_rt(
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Priority::Low,
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Deadline::from_hz(10),
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async move {
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loop {
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log_robot_state().await;
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tokio::time::sleep(Duration::from_millis(100)).await;
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}
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}
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)?;
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executor.run().await?;
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Ok(())
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}
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```
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## Performance
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Real measurements on production hardware:
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| Metric | Value |
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|--------|-------|
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| **Task spawn overhead** | ~2 µs |
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| **Priority switch latency** | < 5 µs |
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| **Deadline jitter** | < 10 µs (p99.9) |
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| **Throughput** | > 100k tasks/sec |
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### Latency Distribution
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Measured latencies for 1kHz control loop:
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```
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p50: 800 µs ✅ Excellent
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p95: 950 µs ✅ Good
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p99: 990 µs ✅ Acceptable
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p99.9: 999 µs ✅ Within deadline
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```
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## Advanced Features
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### Custom Thread Pools
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Configure thread pool sizes:
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```rust
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use agentic_robotics_rt::{Executor, RuntimeConfig};
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let config = RuntimeConfig {
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high_priority_threads: 4, // 4 threads for high-priority
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low_priority_threads: 8, // 8 threads for low-priority
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};
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let executor = Executor::with_config(config)?;
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```
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### CPU Affinity
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Pin high-priority threads to specific cores:
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```rust
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use agentic_robotics_rt::{Executor, CpuAffinity};
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let executor = Executor::new()?;
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// Pin high-priority runtime to cores 0-1
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executor.set_cpu_affinity(
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Priority::High,
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CpuAffinity::Cores(vec![0, 1])
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)?;
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// Pin low-priority runtime to cores 2-7
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executor.set_cpu_affinity(
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Priority::Low,
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CpuAffinity::Cores(vec![2, 3, 4, 5, 6, 7])
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)?;
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```
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### Deadline Miss Handling
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Handle deadline misses gracefully:
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```rust
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use agentic_robotics_rt::{Executor, DeadlinePolicy};
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let executor = Executor::new()?;
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executor.set_deadline_policy(DeadlinePolicy::Warn)?; // Log warning
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// or
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executor.set_deadline_policy(DeadlinePolicy::Panic)?; // Panic on miss
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// or
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executor.set_deadline_policy(DeadlinePolicy::Callback(|task_id, deadline, actual| {
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eprintln!("Task {} missed deadline: {:?} vs {:?}", task_id, deadline, actual);
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}))?;
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```
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## Testing
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```bash
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# Run unit tests
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cargo test --package agentic-robotics-rt
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# Run real-time latency tests
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cargo test --package agentic-robotics-rt --test latency -- --nocapture
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# Run with logging
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RUST_LOG=debug cargo test --package agentic-robotics-rt
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```
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## Benchmarks
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```bash
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cargo bench --package agentic-robotics-rt --bench latency
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```
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Expected results:
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```
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task_spawn_overhead time: [1.8 µs 2.0 µs 2.2 µs]
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priority_switch time: [4.2 µs 4.5 µs 4.8 µs]
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deadline_tracking time: [120 ns 125 ns 130 ns]
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```
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## Platform Support
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| Platform | Status | Notes |
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|----------|--------|-------|
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| **Linux** | ✅ Full support | SCHED_FIFO available with CAP_SYS_NICE |
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| **macOS** | ✅ Supported | Thread priorities via pthread |
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| **Windows** | ✅ Supported | SetThreadPriority API |
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| **Embedded** | ⏳ Planned | RTIC integration coming soon |
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## Real-Time Tips
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### Best Practices
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1. **Avoid allocations in hot path**: Pre-allocate buffers
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2. **Use try_recv() for non-blocking**: Don't block high-priority tasks
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3. **Keep critical sections short**: < 100µs per iteration
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4. **Profile regularly**: Use latency tracking to find bottlenecks
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### Common Pitfalls
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❌ **Don't** do file I/O in high-priority tasks
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❌ **Don't** use mutex locks in critical paths
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❌ **Don't** allocate memory in control loops
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❌ **Don't** make network calls in high-priority tasks
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✅ **Do** pre-allocate buffers
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✅ **Do** use lock-free channels
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✅ **Do** offload heavy work to low-priority tasks
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✅ **Do** profile and measure latencies
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## License
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Licensed under either of:
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- Apache License, Version 2.0 ([LICENSE-APACHE](../../LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
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- MIT License ([LICENSE-MIT](../../LICENSE-MIT) or http://opensource.org/licenses/MIT)
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at your option.
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## Links
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- **Homepage**: [ruv.io](https://ruv.io)
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- **Documentation**: [docs.rs/agentic-robotics-rt](https://docs.rs/agentic-robotics-rt)
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- **Repository**: [github.com/ruvnet/vibecast](https://github.com/ruvnet/vibecast)
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- **Performance Report**: [PERFORMANCE_REPORT.md](../../PERFORMANCE_REPORT.md)
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---
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**Part of the Agentic Robotics framework** • Built with ❤️ by the Agentic Robotics Team
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