PHAROS: Pipelined Heterogeneous Accelerators for Real-time Safety-critical Systems With Deadline Compliance

2026-04-06

AI Summary

Existing heterogeneous accelerator designs primarily prioritize throughput or quality of service, falling short in meeting the stringent requirements of safety-critical real-time systems—namely, predictability, real-time awareness, and rigorous schedulability. This work proposes PHAROS, a novel framework that, for the first time, integrates modern real-time scheduling theory into heterogeneous accelerator design. PHAROS introduces a preemptive scheduling mechanism supporting both FIFO and EDF policies and formulates a soft real-time schedulability analysis model. Building upon this foundation, it develops a schedulability-driven design space exploration algorithm. Experimental results demonstrate that PHAROS significantly improves task set schedulability and real-time responsiveness across diverse applications, uncovering a substantially broader range of feasible configurations compared to throughput-oriented approaches.

Abstract

Spatially partitioned heterogeneous accelerators (HAs) are increasingly adopted in embedded systems for their performance and flexibility. Yet most existing HA design frameworks optimize primarily for throughput or quality-of-service (QoS) metrics. They often overlook safety-critical real-time requirements, including hardware support for predictable execution, real-time-aware design space exploration (DSE), and rigorous schedulability analysis. These requirements are essential in safety-critical applications such as smart transportation, where schedulability guarantees directly affect system safety. To address this gap, we present PHAROS, a real-time-centric HA design framework. PHAROS introduces preemption mechanisms and scheduler designs for spatially partitioned HAs under first-in-first-out (FIFO) and earliest-deadline-first (EDF) policies. Leveraging modern real-time theory, we further develop a soft real-time (SRT) schedulability-oriented DSE with objectives and constraints tailored to SRT schedulability. Through comprehensive modeling, analysis, and evaluation across diverse applications, we show that PHAROS's DSE discovers more feasible configurations for a broader range of task sets than throughput-oriented DSE baselines while delivering improved real-time performance. We also provide response-time analyses for the supported scheduling algorithms.

Problem

• heterogeneous accelerators
• real-time systems
• safety-critical
• schedulability analysis
• design space exploration

Innovation

• heterogeneous accelerators
• real-time scheduling
• schedulability analysis
• design space exploration
• safety-critical systems