NUcache: An Efficient Multicore Cache Organization Based on Next-Use Distance

Proceedings of the 17th International Conference on High Performance Computer Architecture
San Antonio, Texas, February 12--16, 2011

Authors

1. R. Manikantan, Department of Computer Science and Automation
2. Kaushik Rajan, Microsoft Research India, Bangalore
3. R. Govindarajan, Department of Computer Science and Automation

Abstract

The effectiveness of the last-level shared cache is crucial to the performance of a multi-core system. In this paper, we observe and make use of the DelinquentPC—Next-Use characteristic to improve shared cache performance. We propose a new PC-centric cache organization, NUcache, for the shared last level cache of multi-cores. NUcache logically partitions the associative ways of a cache set into MainWays and DeliWays. While all lines have access to the MainWays, only lines brought in by a subset of delinquent PCs, selected by a PC selection mechanism, are allowed to enter the DeliWays. The PC selection mechanism is an intelligent cost-benefit analysis based algorithm that utilizes Next-Use information to select the set of PCs that can maximize the hits experienced in DeliWays.

Performance evaluation reveals that NUcache improves the performance over a baseline design by 9.6%, 30% and 33% respectively for dual, quad and eight core workloads comprised of SPEC benchmarks. We also show that NUcache is more effective than other well-known cache partitioning algorithms.

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