System-Level Observation Framework for Non-Intrusive Runtime Monitoring of Embedded Systems

Abstract

As system complexity continues to increase, the integration of software and hardware subsystems within system-on-a-chip (SOC) presents significant challenges in post-silicon validation, testing, and in-situ debugging across hardware and software layers. The deep integration of software and hardware components within SOCs often prevents the use of traditional analysis methods to observe and monitor the internal state of these components. This situation is further exacerbated for in-situ debugging and testing in which physical access to traditional debug and trace interfaces is unavailable, infeasible, or cost prohibitive. In this dissertation, we present a system-level observation framework (SOF) that provides minimally intrusive methods for dynamically monitoring and analyzing deeply integrated hardware and software components within embedded systems. The SOF monitors hardware and software events by inserting additional logic within hardware cores and by listening to processor trace ports. The SOF provides visibility for monitoring complex execution behavior of software applications without affecting the system execution. The SOF utilizes a dedicated event-streaming interface that allows efficient observation and analysis of rapidly occurring events at runtime. The event-streaming interface supports three alternatives: (1) an in-order priority-based event stream controller, (2) a round-robin priority-based event stream controller, and (3) a priority-level based event stream controller. The in-order priority-based event stream controller, which uses efficient pipelined hardware architecture, ensures that events are reported in-order based on the time of the event occurrence. While the in-order priority-based event stream controller provides high throughput for reporting events, significant area requirement can be incurred. The round-robin priority-based event stream controller is an area-efficient event stream ordering technique with acceptable tradeoffs in event stream throughput. To further reduce area requirement, the SOF supports a priority-level based event stream controller that provides an in-ordering method with smaller area requirements than the round-robin priority-based event stream controller. Comprehensive experimental results using a complete prototype system implementation are presented to quantify the tradeoffs in area, throughput, and latency for the various event streaming interfaces considering several execution scenarios.