QoS-Aware Flash Memory Controller

NAND flash memory has gained a lot of popularity in recent years, widely used in applications ranging from small mobile devices to high-performance enterprise-class storage. However, the variation and unpredictability of performance caused by concurrent flash translation layer (FTL) tasks in a flash storage system are not desirable qualities especially for real-time systems and make it difficult to guarantee the QoS of the storage system. In this paper we present a QoS-aware flash memory controller (QoSFC) designed for predictable performance. For the workload we consider, QoSFC improves not only the average response time by a factor of 12-38 for reads and 1.4-6.9 for writes, but also the 99.9% QoS by a factor of 29-56 for reads and 2.0-8.5 for writes.