PretVM: Predictable, Efficient Virtual Machine for Real-Time Concurrency

TL;DR

PretVM is a virtual machine designed for real-time concurrency, offering predictable timing and deterministic execution for programs with static schedules, improving analyzability and timing guarantees.

Contribution

This paper presents PretVM, a novel virtual machine that executes quasi-static schedules from LF programs with guaranteed worst-case timing bounds.

Findings

PretVM achieves time-accurate deterministic execution.

It provides well-defined worst-case timing bounds.

Experimental results show improved predictability over default LF scheduler.

Abstract

This paper introduces the Precision-Timed Virtual Machine (PretVM), an intermediate platform facilitating the execution of quasi-static schedules compiled from a subset of programs written in the Lingua Franca (LF) coordination language. The subset consists of those programs that in principle should have statically verifiable and predictable timing behavior. The PretVM provides a schedule with well-defined worst-case timing bounds. The PretVM provides a clean separation between application logic and coordination logic, yielding more analyzable program executions. Experiments compare the PretVM against the default (more dynamic) LF scheduler and show that it delivers time-accurate deterministic execution.