Short-Term and Long-Term Idle Time Detectors for Reducing Long-Tail Latency in Solid-State Drives

Solid-state drives (SSDs) using NAND flash memory are the popular storage systems and are widely used in consumer and enterprise systems. Due to the erase-before-write characteristic, NAND flash memory requires time-consuming garbage collection that consists of pages copying and block erasing. Moreover, garbage collection will suspend other I/O requests and cause long-tail latency. In this paper, we propose short-term and long-term idle time detectors to exploit the idle time and reduce the long-tail latency by performing garbage collection on idle time. The experimental results show that our method can reduce the long-tail latency in SSDs.