Asymmetric interactions in symmetric multi-core systems: Analysis, enhancements and evaluation

Multi-core architectures have spurred the rapid growth in high-end computing systems. While the vast majority of such multi-core processors contain symmetric hardware components, their interaction with systems software, in particular the communication stack, results in a remarkable amount of asymmetry in the effective capability of the different cores. In this paper, we analyze such interactions and propose a novel management library called SyMMer (Systems Mapping Manager) that monitors these interactions and dynamically manages the mapping of processes on processor cores to transparently improve application performance. Together with a detailed description of the SyMMer library, we also present performance evaluation comparing SyMMer to a vanilla communication library using various micro-benchmarks as well as popular applications and scientific libraries. Experimental results demonstrate more than a two-fold improvement in communication time and 10-15% improvement in overall application performance.