Deterministic Real-time Thread Scheduling

TL;DR

This paper introduces deterministic real-time scheduling methods for uniprocessor systems that use timing-insensitive events and WCEI to ensure both determinism and real-time guarantees, addressing nondeterminism caused by hardware interactions.

Contribution

It proposes a novel scheduling approach combining deterministic events with WCEI to achieve predictable and real-time thread execution in uniprocessor systems.

Findings

Guarantees deterministic thread execution.

Ensures real-time performance with WCEI.

Reduces nondeterminism from hardware interactions.

Abstract

Race condition is a timing sensitive problem. A significant source of timing variation comes from nondeterministic hardware interactions such as cache misses. While data race detectors and model checkers can check races, the enormous state space of complex software makes it difficult to identify all of the races and those residual implementation errors still remain a big challenge. In this paper, we propose deterministic real-time scheduling methods to address scheduling nondeterminism in uniprocessor systems. The main idea is to use timing insensitive deterministic events, e.g, an instruction counter, in conjunction with a real-time clock to schedule threads. By introducing the concept of Worst Case Executable Instructions (WCEI), we guarantee both determinism and real-time performance.