Improving NVMe SSD I/O determinism with PCIe virtual channel: work-in-progress

Abstract

NVMe SSD over PCIe is attractive since it provides high throughput and low latency. However, complex internal SSD operations may cause a non-deterministic I/O latency which is one of the most important factors in a storage system. While conventional approaches to enhance I/O latency prediction are based on host systems, this paper proposes a novel SSD-based deterministic latency enhancement scheme. The proposed method exploits the fact that multiple virtual channels can be utilized. For each virtual channel, the proposed method assigns a different priority for data transmission. NVMe SSD analyses its internal latency and dynamically chooses the virtual channels to compensate the latency. The experimental results show that, using a PCIe switch model, the proposed method can save 41.6% of the latency for each transaction layer packet.