Virtual Private Machines: A Resource Abstraction for Multi-Core Computer Systems

Virtual Private Machines (VPM) are an abstraction for managing resource sharing in multi-core computer systems. A VPM consists of a complete set of resources, which includes both spatial (microarchitecture) and temporal (processor time slice) resources. Tasks assigned VPMs achieve a minimum level of performance regardless of other tasks in the system – that is, a VPM provides performance isolation. The VPM abstraction provides the interface between a system’s resource management policies and mechanisms. VPM policies, implemented primarily in software, translate system-level performance requirements into VPM assignments. Then VPM mechanisms, implemented in hardware, enforce the VPM assignments. To illustrate the potential of the VPM abstraction, we propose and implement a complete set of VPM policies and mechanisms. The policies translate applications' system-level Quality of Service requirements into VPMs and distribute unassigned and unused resources in order to optimize aggregate system-level performance. A simulation-based study shows that the proposed VPM policies and mechanisms, in combination, provide a high degree of QoS and can significantly improve aggregate performance.