Communication and Execution in Apex.Grace: The Hidden Power Behind High-Performance

Apex.Grace

Purpose-Built for Modern Robotics and Mobility 

At the heart of Apex.Grace is a purpose-built system by Apex.AI to meet the demands of real-time, embedded, and safety-critical environments. This executor isn’t just fast—it’s deterministic. That means predictable behavior, low latency, and minimal jitter, even under massive workloads. 

Paired with Apex.Ida, our high-performance communication middleware, Apex.Grace becomes part of a tightly integrated stack. This integration eliminates common bottlenecks, such as copying messages or frequent context switching.  

And the results speak for themselves: 

• Scaling up to hundreds of gigabits per second of data throughput 

• Scaling up to Tens of thousands of message transfers per second 

• Enabling real-time systems with high responsiveness and low overhead 

High-Performance Communication You Can Trust 

Apex.Grace uses familiar ROS 2 publish/subscribe and request/reply communication patterns, built on the ROS Interface Definition Language (IDL) and aligned with the DDS standard. But unlike generic implementations, our communication stack is optimized for safety-critical systems. 

Some key enhancements: 

• Loaned messages let publishers write directly into middleware buffers, speeding up large message handling with zero-copy communication. 

• Polling-based subscribers and services reduce context switches by waking threads only when needed. 

• Fine-grained control over message caching with the DDS history QoS enables smarter data flow. 

These are not just features—they’re enablers of consistent, scalable, real-time performance. 

A Smarter Way to Execute Work 

The Apex.Grace executor goes far beyond traditional models using message callbacks. It introduces a flexible architecture based on executable items—small, non-blocking actions that are combined into tasks. These tasks can be triggered by messages, timers, or file descriptors. 

System integrators can define tasks with: 

• A single executable item 

• Sequential chains of items 

• Directed acyclic graphs (DAGs) of items executed with a thread pool 

• This separation of logical structure from execution policy means your application logic stays clean, while integrators fine-tune performance for the real world. 

You also get full control over: 

• Thread priorities 

• Core affinities 

• Scheduling policies 

This is especially valuable when deploying to systems with real-time or mixed-criticality requirements. 

Real-Time Scheduling with Precision 

To keep everything in sync, Apex.Grace includes a real-time-capable timer service. Whether you need periodic updates or one-shot events, timers are tightly integrated with the executor and built to meet the needs of deterministic systems. 

You can: 

• Trigger work directly from timers 

• Schedule tasks with precise intervals and phase alignment 

• Reproduce timer behavior for deterministic replay and verification 

This makes Apex.Grace is not only performant but verifiable—a critical requirement for certified systems. 

A Glimpse at What’s Next: Logical Execution Time 

While still in proof-of-concept, Logical Execution Time (LET) is the next frontier. LET gives every task a fixed logical time window, decoupling execution from physical clock timing. This enables reproducible behavior and race-free designs, especially in high-integrity systems. 

When paired with Apex.Grace’s deterministic executor, LET, offers: 

• Synchronized inputs and outputs 

• Time-predictable execution 

• Safer integration across distributed systems 

Watch this space. 

Why This Matters 

When teams look beyond prototyping and toward production, they often discover that communication and execution are where performance either excels or breaks down. 

With Apex.Grace, we’ve built a system that scales, is fast, reliable, and ready for certification, and gives you control. 

Ready to transform your system from capable to certifiable? Let’s talk. Apex.Grace combines communication and execution to enable confident scaling.

Contact us to learn how Apex.Grace can support your path to production.