Dynamic Task-to-chip Allocation for Real-time I/O Guarantees in Flash Storage Systems

Abstract

The goal of this paper is to provide worst-case timing guarantees for real-time I/O requests, while fully utilizing the potential bandwidth for non real-time I/O requests in NAND flash storage systems. We identify a trade-off between flash chip sharing and I/O workload isolation in terms of timing guarantees and bandwidth. By taking such a trade-off into account, we propose a new real-time I/O scheduling framework that enables dynamic isolation between real-time I/O requests to meet all timing constraints and co-scheduling of real-time and non real-time I/O requests to provide high bandwidth utilization. Our in-depth evaluation results show that the proposed approach outperforms existing isolation approaches significantly in terms of both schedulability and bandwidth.