Distance-aware L2 cache organizations for scalable multiprocessor systems

In order to provide the scalability to the multiprocessor systems, it is important to keep the remote memory access time in bounds so that it does not impose much additional overhead as the system grows. In this paper, we suggest an LRU/distance-aware combined second-level(L2) cache for scalable CC-NUMA multiprocessors, which is composed of a traditional LRU cache and an additional distance-aware cache that maintains the distance information of individual cache block for replacement purposes. The LRU cache selects a victim using age information as it typically does, while the distance-aware cache does using distance information. Both work together to reduce effectively the overall distance the cache miss goes through by keeping long-distance blocks as well as recently used blocks. It has been observed that the proposed cache outperforms the traditional LRU cache by up to 28% in the execution time. It is also found to perform even better than an LRU cache of twice the size.