RELOCATE: Register file local access pattern redistribution mechanism for power and thermal management in out-of-order embedded processor

Abstract

In order to reduce register file's peak temperature in an embedded processor we propose RELOCATE: an architectural solution which redistributes the access pattern to physical registers through a novel register allocation mechanism. RELOCATE regionalizes the register file such that even though accesses within a region are uniformly distributed, the activity levels are spread over the entire register file in a deterministic pattern. It partitions the register file and uses a micro-architectural mechanism to concentrate the accesses to a single or a subset of such partitions through a novel register allocation mechanism. The goal is to keep some partitions unused (idle) and cooling down. The temperature of idle partitions is further reduced by power gating them into destructive sleep mode to reduce their leakage power. The redistribution mechanism changes the active region periodically to modulate the activity within the register file and prevent the active region from heating up excessively. Our approach resulted in an average reduction of 8.3°C in the register file's peak temperature for standard benchmarks. © 2010 Springer-Verlag.