Abstract: Cache is a processor feature that can greatly affect the performance of programs. The averagecase performance of most recently used(MRU) Cache replacement policy was studied. Research results showed that MRU outperforms LRU in some circumstances. By analyzing loop structures with sequential memory accesses， the condition for this phenomenon is given and formally proved. Extensive experiments were conducted on realtime timing analysis benchmarks for different Cache configurations， which shows that MRU outperforms LRU in lots of execution scenarios. Combining this result and recent results on the realtime performance of MRU replacement policy， it can be concluded that MRU has very high performance in both averagecase and realtime metrics.

Key words: MRU(most recently used), Cache, replacement policy, averagecase performance, realtime performance