docs: add sglang hicache example and guide (#2388)

components/backends/sglang/README.md

@@ -179,6 +179,9 @@ Below we provide a selected list of advanced examples. Please open up an issue i
 ### Supporting SGLang's native endpoints via Dynamo
 - **[HTTP Server for native SGLang endpoints](docs/sgl-http-server.md)**
 
+### Hierarchical Cache (HiCache)
+- **[Enable SGLang Hierarchical Cache (HiCache)](docs/sgl-hicache-example.md)**
+
 ## Deployment
 
 We currently provide deployment examples for Kubernetes and SLURM.

components/backends/sglang/docs/sgl-hicache-example.md

+<!--
+SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+SPDX-License-Identifier: Apache-2.0
+-->
+
+# Enable SGLang Hierarchical Cache (HiCache)
+
+This guide shows how to enable SGLang's Hierarchical Cache (HiCache) inside Dynamo.
+
+## 1) Start the SGLang worker with HiCache enabled
+
+```bash
+python -m dynamo.sglang.worker \
+  --model-path deepseek-ai/DeepSeek-R1-Distill-Llama-8B \
+  --host 0.0.0.0 --port 8000 \
+  --page-size 64 \
+  --enable-hierarchical-cache \
+  --hicache-size 30 \
+  --hicache-write-policy write_through \
+  --hicache-storage-backend nixl \
+  --log-level debug \
+  --skip-tokenizer-init
+```
+
+- **--enable-hierarchical-cache**: Enables hierarchical KV cache/offload
+- **--hicache-size**: HiCache capacity in GB of pinned host memory (upper bound of offloaded KV to CPU)
+- **--hicache-write-policy**: Write policy (e.g., `write_through` for synchronous host writes)
+- **--hicache-storage-backend**: Host storage backend for HiCache (e.g., `nixl`). NIXL selects the concrete store automatically; see [PR #8488](https://github.com/sgl-project/sglang/pull/8488)
+
+
+Then, start the frontend:
+```bash
+python -m dynamo.frontend --http-port 8000
+```
+
+## 2) Send a single request
+
+```bash
+curl localhost:8000/v1/chat/completions \
+  -H "Content-Type: application/json" \
+  -d '{
+    "model": "deepseek-ai/DeepSeek-R1-Distill-Llama-8B",
+    "messages": [
+      {
+        "role": "user",
+        "content": "Explain why Roger Federer is considered one of the greatest tennis players of all time"
+      }
+    ],
+    "stream": false,
+    "max_tokens": 30
+  }'
+```
+
+## 3) (Optional) Benchmarking
+
+Run the perf script:
+```bash
+bash -x /workspace/benchmarks/llm/perf.sh \
+  --model deepseek-ai/DeepSeek-R1-Distill-Llama-8B \
+  --tensor-parallelism 1 \
+  --data-parallelism 1 \
+  --concurrency "2,4,8" \
+  --input-sequence-length 2048 \
+  --output-sequence-length 256
+```