A novel I/O scheduler for SSD with improved performance and lifetime

This paper presents a novel block I/O scheduler specifically for SSDs. The scheduler leverages the internal rich parallelism resulting from SSD´s highly parallelized architecture. It speculatively divides the entire SSD space into different subregions and dispatches requests into those subregions in a round-robin fashion at the Linux kernel block layer. In the meanwhile, to reduce the severe read-write interference problem associated with SSDs, the scheduler only dispatches a batch of unidirectional requests to the disk driver for each subregion´s scheduling opportunity. Furthermore, to take advantage of SSD´S better sequential performance over random patterns, the scheduler sorts the pending requests while they are awaiting in the dispatching queues as those HDD-oriented schedulers do. The experimental results with a variety of workloads have demonstrated that the new I/O scheduler not only improves the user-perceived performance, but also enhances the underlying SSD´s lifetime via reducing the block erase operations during the running processes.