X-ray: a tool for automatic measurement of hardware parameters

There is growing interest in self-optimizing computing systems that can optimize their own behavior on different platforms without manual intervention. Examples of successful self-optimizing systems are ATLAS, which generates basic linear algebra subroutine (BLAS) libraries, and FFTW, which generates FFT libraries. Self-optimizing systems need values for hardware parameters such as the number of registers of various types and the capacities of caches at various levels. For example, ATLAS uses the capacity of the LI cache and the number of registers in determining the size of cache tiles and register tiles. In this paper, we describe X-ray, a system for implementing micro-benchmarks to measure such hardware parameters. We also present novel algorithms for measuring some of these parameters. Experimental evaluations of X-ray on traditional workstations, servers and embedded systems show that X-ray produces more accurate and complete results than existing tools.