计算机系柴云鹏老师的论文被IEEE Transactions on Computers录用

近日，我院计算机系柴云鹏老师的论文《WEC: Improving Durability of SSD Cache Drives by Caching Write-Efficient Data》被IEEE Transactions on Computers（TC）录用。TC是计算机系统结构领域顶级的国际期刊，也是中国计算机学会认定的体系结构方向的三个A类期刊之一。TC的历史可追溯至1952年，迄今已有64年历史，是计算机领域历史最悠久的期刊之一。

该论文针对现有SSD缓存写入量过多、使用寿命较短的问题，在国际上率先提出用“拉模式”的缓存数据更新方法替换传统的“推模式”，延长热门数据在SSD缓存中的停留时间。该文所提出的WEC算法，可以在相近缓存命中率的前提下，将SSD缓存的写入需求下降两个数据级，显著延长了SSD缓存的使用寿命和系统可靠性。

论文的摘要为：Serving as cache disks, flash-based solid-state drives (SSDs) can significantly boost the performance of read-intensive applications. However, frequent data updating, the necessary condition for classical replacement algorithms (e.g., LRU, MQ, LIRS, and ARC) to achieve a high hit rate, makes SSDs wear out quickly. To address this problem, we propose a new approach—write-efficient caching (WEC)—to greatly improve the write durability of SSD cache. WEC is conducive to reducing the total number of writes issued to SSDs while achieving high hit rates. WEC takes two steps to improve write durability and performance of SSD cache. First, WEC discovers write-efficient data, which tend to be active for a long time period and to be frequently accessed. Second, WEC keeps the write-efficient data in SSDs long enough to avoid excessive number of unnecessary updates. Our findings based on a wide range of popular real-world traces show that write-efficient data does exist in a wide range of popular read-intensive applications. Our experimental results indicate that compared with the classical algorithms, WEC judiciously improves the mean hits of each written block by approximately two orders of magnitude while exhibiting similar or even higher hit rates.