Improving The Performance Of Parallel Organization Of Hybrid Memory System Based On Phase Change Memory

The memory system is one of fundamental performance bottlenecks in almost all computing systems.And the problem of power dissipation in the memory system is becoming more and more serious.Recent system designs,applications,and technology trends require more capacity,bandwidth and efficiency.Current memory technology is experiencing huge challenges.Nonvolatile memory,such as Phase Change Memory(PCM),brings the opportunity to the development of memory technology.PCM has the advantage of large capacity and no refresh power consumption.Incorporating PCM into the memory hierarchy can not only increase capacity,but also reduce the power dissipation.To settle the problem that the migration strategy used in page replacement algorithm may lead to decrease of main memory hit rate,we propose a new page replacement algorithm—MQ-LRU.A new migration strategy that exchange data when migrating is used in new algorithm to avoid the decrease of hit rate caused by releasing page when migrating.This algorithm use multi queues to evaluate the write tendency of pages.To reduce the write operation on PCM,it move the write-intensive page from PCM to DRAM.Due to the poor write performance of PCM,A numerous writes directly to PCM affect the efficiency of parallel organization of DRAM-PCM hybrid memory.To solve this problem,a write buffer is used in PCM of parallel organization of DRAM-PCM hybrid memory to hide the poor write performance of PCM.Tests and analysis about above algorithm and organization have been conducted.The experiment results indicates that new algorithm can increase the hit rate and reduce writes on PCM.And the new parallel organization improve the throughput by 18.7% on average.