Using complete system simulation for temporal debugging of general purpose operating systems and workloads

Digital convergence is precipitating the addition of soft real-time applications to mainstream desktop and server operating environments. Most traditional debuggers for mainstream systems lack a notion of temporal correctness, making them unsuitable for real-time system design and analysis. We propose leveraging complete system simulation to build a temporal debugger which is capable of analyzing mixed real-world workloads. Traditional real-time system debuggers based on simulation utilize slow, but accurate, simulators. Complete system simulators accept an approximate model of time in exchange for higher performance. The higher performance allows these simulators to analyze high-end commercial operating systems and applications. We describe a temporal debugger design based on complete system simulation and report on some early experiences in analyzing a simple workload. The tool offers a non-intrusive, predictable environment for debugging complex workloads with partial real-time constraints. The simulator foundation allows for interactive debugging of time-critical sequences while preserving a model of execution time flow.