Two Cooperative Partitions for the Lase Level Cache

AbstractCurrently the most widely used replacement policy in the last cache is the LRU algorithm. Popular as it is, LRU performs poorly when it has a memory-intensive workload whose working set is larger than the available cache capacity. The algorithm evicts a line without taking into account its longer history of usage. The result is that some live lines may be replaced by some newly-referenced blocks, though it is possible that the new blocks will never be used again in the future.Hence, improving the replacement policy is critical to the improvement of cache efficiency and the overall system performance. In this paper we present a technique to retain the live line in the cache while evicting the dead line early by dividing the last level cache into two cooperative partitions (TCP), both of which use the LRU replacement policy. When a live line is evicted from one partition, it will be placed into the other partition. This new technique named TCP, as observed in our experiment, achieved an L2 cache miss rate reduction of 9.8% on average with fifteen benchmarks from the SPEC CPU2000 suite, and resulted in an IPC improvement of 2.4% on average