A novel low-overhead flexible instrumentation framework for virtual platforms

Instrumentation methods for code profiling, tracing and semihosting on virtual platforms (VP) and instruction-set simulators (ISS) rely on function call and system call interception. To reduce instrumentation overhead that can affect program behavior and timing, we propose a novel low-overhead flexible instrumentation framework called Virtual Platform Instrumentation (VPI). The VPI framework uses a new table-based parameter-passing method that reduces the runtime overhead of instrumentation to only that of the interception. Furthermore, it provides a high-level interface to extend the functionality of any VP or ISS with debugging support, without changes to their source code. Our framework unifies the implementation of tracing, profiling and semihosting use cases, while at the same time reducing detrimental runtime overhead on the target as much as 90% compared to widely deployed traditional methods, without significant simulation time penalty.