CLOCK-RWRF: A Read-Write-Relative-Frequency Page Replacement Algorithm for PCM and DRAM of Hybrid Memory

Abstract

Recently, with development of data-intensive applications, the traditional DRAM-based memory cannot satisfy the capacity requirement. Phase Change Memory (PCM), which is one of the non-volatile memories, has potentials in high density and low leakage power, and has been emerged as a promising candidate to replace traditional DRAM-based memory. However, owing to the weakness in write endurance and write latency, integrating PCM in hybrid memory faces the enormous challenges. To achieve the most performance improvement and maximize the life span of PCM, we prefer to allocate the excessive write operations to DRAM and read operations to PCM. In this paper, we propose a novel page management policy called CLOCK-RWRF that aggressively decreases write operations of PCM and at the same time maintains the high hit ratio. CLOCK-RWRF uses the relative frequency about read and write operation in a page to judge whether the page is write-intensive or not and push write-intensive page into DRAM. Simulation results show that compared to other algorithms, CLOCK-RWRF can significantly reduce write count on PCM and energy consumption on hybrid memory and has a high hit ratio as similar as CLOCK algorithm.