Add Doc: Mapping a Single GPU (#33)

Author: liu-shaojun

vllm/README.md

@@ -179,6 +179,20 @@ docker exec -it lsv-container bash
 
 ---
 
+**Note — Mapping a Single GPU**
+> If you need to map only a specific GPU into the container, remove both `--privileged` and `--device=/dev/dri` from the `docker run` command, and replace them with the following device and mount options (example for the first GPU):
+
+```bash
+--device /dev/dri/renderD128:/dev/dri/renderD128 \
+--mount type=bind,source="/dev/dri/by-path/pci-0000:18:00.0-card",target="/dev/dri/by-path/pci-0000:18:00.0-card" \
+--mount type=bind,source="/dev/dri/by-path/pci-0000:18:00.0-render",target="/dev/dri/by-path/pci-0000:18:00.0-render" \
+-v /dev/dri/card0:/dev/dri/card0 \
+```
+
+This way, only the first GPU will be mapped into the Docker container.
+
+---
+
 ### 1.4 Launching the Serving Service
 
 ```bash