An Instrumentation Approach for Hardware-Agnostic Software Characterization

Simulators and empirical profiling data are often used to understand how suitable a specific hardware architecture is for an application. However, simulators can be slow, and empirical profiling-based methods can only provide insights about the existing hardware on which the applications are executed. While the insights obtained in this way are valuable, such methods cannot be used to evaluate a large number of system designs efficiently. Analytical performance evaluation models are fast alternatives, particularly well-suited for system design-space exploration. However, to be truly application-specific, they need to be combined with a workload model that captures relevant application characteristics. In this paper we introduce PISA, a framework based on the LLVM infrastructure that is able to generate such a model for sequential and parallel applications by performing hardware-independent characterization. Characteristics such as instruction-level parallelism, memory access patterns and branch behavior are analyzed per thread or process during application execution. To illustrate the potential of the framework, we provide a detailed characterization of a representative benchmark for graph-based analytics, Graph 500. Finally, we analyze how the properties extracted with PISA across Graph 500 and SPEC CPU2006 applications compare to measurements performed on x86 and POWER8 processors.