Adaptive thread and memory access schelduling in chip multiprocessors

Abstract

The full potential of chip multiprocessors remains unexploited due to architecture oblivious thread schedulers used in operating systems, and thread-oblivious memory access schedulers used in off-chip main memory controllers. For the thread scheduling, we introduce an adaptive cache-hierarchy-aware scheduler that tries to schedule threads in a way that inter-thread contention is minimized. A novel multi-metric scoring scheme is used that specifies the L1 cache access characteristics of a thread. The scheduling decisions are made based on multi-metric scores of threads. For the memory access scheduling, we introduce an adaptive compute-phase prediction and thread prioritization scheme that efficiently categorize threads based on execution characteristics and provides fine-grained prioritization that allows to differentiate threads and prioritize their memory access requests accordingly.