NVMeVirt: A Versatile Software-defined Virtual NVMe Device

on YouTube ↗18m

" summary

Kernel module creates a real-looking virtual PCI device via a virtual PCI bus, runs a dispatcher thread that polls doorbells and splits NVMe commands into backend ops, and moves payloads with the DMA engine into main-memory-backed storage. Implementation is 9,000 lines of Linux C code and models a parallel FTL with GC to emulate channels/planes. It supports PCI peer-to-peer DMA and NVMe-oF offload and reproduces device performance closely (harmonic-mean error ~1.17%). In a case study, configured devices at 2.5–3.0 GB/s show MariaDB uses <0.5 GB/s while PostgreSQL consumes the high bandwidth.

AI-written summary · about

" chapters (15)

1. 0:00Intro
2. 0:23Once upon a time in our research...
3. 1:54Dilemma of Emulator
4. 2:46Previous: Device Driver-level Approaches
5. 3:58Previous: Virtualization-based Approaches
6. 5:02NVMeVirt: Virtual NVMe Device in Software
7. 6:26Challenges for Virtual PCI/NVMe Devices
8. 8:44Emulating NVMe Device: Configuration Requests
9. 9:09Emulating NVMe Device: I/O Requests
10. 11:20Performance Models
11. 12:20Evaluation
12. 13:12Emulation Quality: Performance Variance
13. 14:33Performance Comparison to Real Devices
14. 15:07Performance Characteristics Compared to Real De
15. 15:37Case Study: DBMS on Various Storage Configuratio