REMUS: Efficient Multi-Request Scheduling in Computational Storage Devices

Data-intensive applications benefit from offloading data processing to storage devices with embedded cores, typically Computational Storage Device (CSD). Co-locating requests from different applications to one CSD offers better performance and power efficiency than dedicating CSDs to a single application. However, current CSD scheduling frameworks fail to handle the contention in CPU, Flash I/O and buffer due to mismatching of resources and the requests, leading to sub-optimal performance. This paper proposes REMUS, a CSD scheduling framework handling multiple requests for CSD platforms with multiple homogeneous cores. The key idea of REMUS is to allocate the workload to multiple cores according to the distribution of the Logical Block Address (LBA) of the requests and mitigate stall time by sorting requests based on their urgency of demand for resources, where urgency is quantified by the current remaining buffer capacity of the requests. Furthermore, a buffer allocation scheme is proposed to avoid programs that exclusively occupy the resources. We conduct experiments on both a simulator and a real CSD platform. The experiment results show that REMUS improved throughput by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1.51} \times$</tex> on the simulator and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1.39} \times$</tex> on the real platform on average compared to the baselines.