Architectural approach for dynamic thermal management at high density rack-mounted servers

Abstract

High power densities and the implications of high operating temperatures on the failure rates of components are key driving factors of temperature-aware computing. The subject of this thesis is to propose thermal management scheme responding this thermal problem in di®erent granularity of computer system such as processor, server and rack. For thermal issues on processor, elevated on-chip temperatures due to high performance has an adverse e®ect on cooling solution cost and, if not addressed suitably, on chip reliability. On server/rack, computer architects and system software designers need to understand the thermal consequences of their proposals, and develop techniques to lower operating temperatures to reduce both transient and permanent component failures. Until recently, tools for understanding temperature rami¯cations of designs of server and rack have been mainly restricted to industry for studying packaging and cooling mechanisms, with little access to such toolsets for academic researchers. Developing such tools is an arduous task since it usually requires cross-cutting areas of expertise spanning architecture, systems software, thermodynamics, and cooling systems. Recognizing the need for such tools, there has been recent work on modeling temperatures of processors at the micro-architectural level which can be easily understood and employed by computer architects for processor designs. However, there is a dearth of such tools in the academic/research community for undertaking architectural/systems studies beyond a processor - a server box, rack or even a machine room. In this thesis we investigate the general trade-o®s between temporal and spatial hot spot mitigation schemes and thermal time constants, workload variations and microprocessor power distributions. By leveraging spatial and temporal heat slacks, our schemes enable lowering of on-chip unit temperatures by changing the workload in a timely manner with Operating System(OS) and e...