Merge pull request #1 from metaspace/nvme

update NVMe page

Author: ojeda

SUMMARY.md

@@ -20,7 +20,7 @@
 
 ## Users
 
-  - [NVMe driver](NVMe-driver.md)
+  - [NVMe Driver](NVMe-driver.md)
 
 # Links
 

src/NVMe-driver.md

@@ -1,5 +1,59 @@
-# NVMe driver
+# NVMe Driver
 
-The Rust [NVMe driver](https://github.com/metaspace/linux/tree/nvme) is an effort to implement a PCI NVMe driver in safe Rust for use in the Linux Kernel. The purpose of the driver is to provide a vehicle for development of safe Rust abstractions and to prove feasibility of Rust as an implementation language for high performance device drivers.
+The Rust NVMe driver is an effort to implement a PCI NVMe driver in safe Rust
+for use in the Linux Kernel. The purpose of the driver is to provide a vehicle
+for development of safe Rust abstractions and to prove feasibility of Rust as an
+implementation language for high performance device drivers.
 
-The Rust NVMe driver was originally authored by Wedson Almeida Filho and is now maintained by Andreas Hindborg (Samsung).
+The Linux Rust NVMe driver lives
+[here](https://github.com/metaspace/linux/tree/nvme). Please be aware that the
+nvme branch is force pushed without notice. The Rust NVMe driver was originally
+authored by Wedson Almeida Filho and is now maintained by Andreas Hindborg
+(Samsung).
+
+The driver is not currently suitable for general use.
+
+# Resources
+ - LPC 2022
+   [slides](https://lpc.events/event/16/contributions/1180/attachments/1017/1961/deck.pdf)
+   and [video](https://lpc.events/event/16/contributions/1180/attachments/1017/2249/go)
+
+# Performance
+
+Performance evaluation as of January 2023. 
+
+## Setup
+
+- Dell PowerEdge R6525
+- 1 CPU socket populated - EPYC 7313, 16 cores
+- 128 GB DRAM
+- 3x P5800x 16GT/s x4 7.88 GB/s (PCIe 4)
+- Debian bullseye (linux 5.19.0+)
+
+## Results
+
+![iops](./iops.svg)
+![relative](./relative.svg)
+
+## Analysis
+
+For 4 KiB block size, the Rust NVMe driver performs similar to the C driver. For
+this configuration the target drive is bandwidth limited.
+
+For 512 B block size, the C driver outperforms the Rust driver by up to 6%. In
+this configuration the drive is not bandwidth limited, but the benchmark becomes
+compute limited. The Rust driver has a higher overhead and thus performs worse.
+
+# Planned Work Items
+
+  - Remove all unsafe code from the driver
+  - Support device removal
+  - Verify functionality by executing `blktests` and `xfstests` in CI
+  - Add sys-fs nodes to allow use of nvme-cli with Rust NVMe driver
+  - Support more kernel configurations by deferring initialization to a task queue
+  - Improve performance of Rust NVMe driver
+
+# Contact
+
+Please contact Andreas Hindborg through
+[Zulip](Contact.md#zulip-chat).