MPSoC Software Debugging on Virtual Platforms via Execution Control with Event Graphs

Abstract

Virtual Platforms (VPs) are advantageous to develop and debug complex software for multi- and many-processor systems-on-chip (MPSoCs). VPs provide unrivaled controllability and visibility of the target, which can be exploited to examine bugs that cannot be reproduced easily in real hardware (e.g., bugs originating from races or happening during a processor stand-by state). However, VPs as employed in practice for debugging are generally underutilized. The accompanying debug ecosystem is based mostly on traditional tools, such as step-based debuggers and traces, that fall short to address the enormous complexity of modern MPSoCs and their parallel software. Finding a bug is still largely left to the developer’s experience and intuition, using manual means rather than automated or systematic solutions that exploit the controllability and visibility of VPs. Profiting from VPs for MPSoC software debugging is an open question. To bridge this gap, this article presents a novel framework for debug visualization and execution control that, relying on the many benefits of VPs, helps to identify and test possible concurrency-related bug scenarios. The framework allows examining and steering the target system by manipulating an abstract graph that highlights relevant inter-component interactions and dependencies. The proposed framework reduces the effort required to understand complex concurrency patterns and helps to expose bugs. Its efficacy is demonstrated on (i) a shared memory symmetric multi-processing platform executing Linux and parallel benchmarks, and (ii) a distributed automotive system for driver assistance applications.