As solid-state drives (SSDs) with sufficient computing power have recently become the dominant devices in modern computer systems, in-storage processing (ISP), which processes data within the storage without transferring it to the host memory, is being utilized in various emerging applications. The main challenge of ISP is to deliver storage data to the offloaded workload. This is difficult because of the information gap between the host and storage, the data consistency problem between the host and offloaded workloads, and SSD-specific hardware limitations. Moreover, because the offloaded workloads use internal SSD resources, host I/O performance might be degraded due to resource conflicts. Although several ISP frameworks have been proposed, existing ISP approaches that do not deeply consider the internal SSD behavior are often insufficient to support efficient ISP workload offloading with high programmability.

In this article, we propose an ISP agent, a lightweight ISP workload offloading framework for SSD devices. The ISP agent provides I/O and memory interfaces that allow users to run existing function codes on SSDs without major code modifications, and separates the resources for the offloaded workloads from the existing SSD firmware to minimize interference with host I/O processing. The ISP agent also provides further optimization opportunities for the offloaded workload by considering SSD architectures. We have implemented the ISP agent on the OpenSSD Cosmos+ board and evaluated its performance using synthetic benchmarks and a real-world ISP-assisted database checkpointing application. The experimental results demonstrate that the ISP agent enhances host application performance while increasing ISP programmability, and that the optimization opportunities provided by the ISP agent can significantly improve ISP-side performance without compromising host I/O processing.

随着具有足够计算能力的固态硬盘（SSD）最近成为现代计算机系统中的主导设备，存储内处理（ISP）在存储中处理数据而不将其传输到主机内存，正在被应用于各种领域。新兴应用。ISP 的主要挑战是将存储数据交付给卸载的工作负载。由于主机和存储之间的信息差距、主机和卸载的工作负载之间的数据一致性问题以及 SSD 特定的硬件限制，这很困难。此外，由于卸载的工作负载使用内部 SSD 资源，因此主机 I/O 性能可能会因资源冲突而降低。尽管已经提出了几种 ISP 框架，但现有的 ISP 方法没有深入考虑内部 SSD 行为，通常不足以支持具有高可编程性的高效 ISP 工作负载卸载。

在本文中，我们提出了一种 ISP 代理，这是一种用于 SSD 设备的轻量级 ISP 工作负载卸载框架。ISP代理提供I/O和内存接口，允许用户在SSD上运行现有功能代码而无需进行重大代码修改，并将用于卸载工作负载的资源与现有SSD固件分开，以最大限度地减少对主机I/O处理的干扰。ISP 代理还通过考虑 SSD 架构为卸载的工作负载提供进一步的优化机会。我们在 OpenSSD Cosmos+ 板上实现了 ISP 代理，并使用综合基准和真实的 ISP 辅助数据库检查点应用程序评估了其性能。实验结果表明，ISP代理增强了主机应用程序性能，同时增加了ISP可编程性，并且ISP代理提供的优化机会可以在不影响主机I/O处理的情况下显着提高ISP端性能。