A dynamically reconfigurable cache for multithreaded processors

Abstract

Chip multi-processors (CMP) are rapidly emerging as an important design paradigm for both high performance and embedded processors. These machines provide an important performance alternative to increasing the clock frequency. In spite of the increase in potential performance, several issues related to resource sharing on the chip can negatively impact the performance of embedded applications. In particular, the shared on-chip caches make each job's memory access times dependent on the behavior of the other jobs sharing the cache. If not adequately managed, this can lead to problems in meeting hard real-time scheduling constraints. This work explores adaptable caching strategies which balance the resource demands of each application and in turn lead to improvements in throughput for the collective workload. Experimental results demonstrate speedups of up to 1.47X for workloads of two co-scheduled applications compared against a fully-shared two-level cache hierarchy. Additionally, the adaptable caching scheme is shown to achieve an average speedup of 1.10X over the leading cache partitioning model. By dynamically managing cache storage for multiple application threads at runtime, sizable performance levels are achieved, which provides chip designers the opportunity to maintain high performance as cache size and power budgets become a concern in the CMP design space.