Doc: Add Docs about EAGLE speculative decoding (#3144)

Co-authored-by: Chayenne <zhaochenyang@ucla.edu>
Co-authored-by: zhaochenyang20 <zhaochen20@outlook.com>

docs/backend/speculative_decoding.ipynb

+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Speculative Decoding\n",
+    "\n",
+    "SGLang now provides an EAGLE-based speculative decoding option. The implementation aims to maximize speed and efficiency and is considered to be among the fastest in open-source LLM engines.\n",
+    "\n",
+    "### Performance Highlights\n",
+    "\n",
+    "- **Official EAGLE code** ([SafeAILab/EAGLE](https://github.com/SafeAILab/EAGLE)): ~200 tokens/s\n",
+    "- **Standard SGLang Decoding**: ~156 tokens/s\n",
+    "- **EAGLE Decoding in SGLang**: ~297 tokens/s\n",
+    "- **EAGLE Decoding in SGLang (w/ `torch.compile`)**: ~316 tokens/s\n",
+    "\n",
+    "All benchmarks below were run on a single H100."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## EAGLE Decoding\n",
+    "\n",
+    "To enable EAGLE-based speculative decoding, specify the draft model (`--speculative-draft`) and the relevant EAGLE parameters:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# EAGLE decoding\n",
+    "from sglang.utils import (\n",
+    "    execute_shell_command,\n",
+    "    wait_for_server,\n",
+    "    terminate_process,\n",
+    "    print_highlight,\n",
+    ")\n",
+    "\n",
+    "server_process = execute_shell_command(\n",
+    "    \"\"\"\n",
+    "python3 -m sglang.launch_server --model meta-llama/Llama-2-7b-chat-hf  --speculative-algo EAGLE \\\n",
+    "    --speculative-draft lmzheng/sglang-EAGLE-llama2-chat-7B --speculative-num-steps 5 \\\n",
+    "    --speculative-eagle-topk 8 --speculative-num-draft-tokens 64 --mem-fraction 0.7 --port=30020\n",
+    "\"\"\"\n",
+    ")\n",
+    "\n",
+    "wait_for_server(\"http://localhost:30020\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import openai\n",
+    "\n",
+    "client = openai.Client(base_url=\"http://127.0.0.1:30020/v1\", api_key=\"None\")\n",
+    "\n",
+    "response = client.chat.completions.create(\n",
+    "    model=\"meta-llama/Meta-Llama-3.1-8B-Instruct\",\n",
+    "    messages=[\n",
+    "        {\"role\": \"user\", \"content\": \"List 3 countries and their capitals.\"},\n",
+    "    ],\n",
+    "    temperature=0,\n",
+    "    max_tokens=64,\n",
+    ")\n",
+    "\n",
+    "print_highlight(f\"Response: {response}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "terminate_process(server_process)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### EAGLE Decoding with `torch.compile`\n",
+    "\n",
+    "You can also enable `torch.compile` for further optimizations and optionally set `--cuda-graph-max-bs`:\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "server_process = execute_shell_command(\n",
+    "    \"\"\"\n",
+    "python3 -m sglang.launch_server --model meta-llama/Llama-2-7b-chat-hf  --speculative-algo EAGLE \\\n",
+    "    --speculative-draft lmzheng/sglang-EAGLE-llama2-chat-7B --speculative-num-steps 5 \\\n",
+    "        --speculative-eagle-topk 8 --speculative-num-draft-tokens 64 --mem-fraction 0.7 \\\n",
+    "            --enable-torch-compile --cuda-graph-max-bs 2 --port=30020\n",
+    "\"\"\"\n",
+    ")\n",
+    "\n",
+    "wait_for_server(\"http://localhost:30020\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Benchmark Script\n",
+    "\n",
+    "The following code example shows how to measure the decoding speed when generating tokens:\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import time\n",
+    "import requests\n",
+    "\n",
+    "tic = time.time()\n",
+    "response = requests.post(\n",
+    "    \"http://localhost:30020/generate\",\n",
+    "    json={\n",
+    "        \"text\": \"[INST] Give me a simple FastAPI server. Show the python code. [/INST]\",\n",
+    "        \"sampling_params\": {\n",
+    "            \"temperature\": 0,\n",
+    "            \"max_new_tokens\": 256,\n",
+    "        },\n",
+    "    },\n",
+    ")\n",
+    "latency = time.time() - tic\n",
+    "ret = response.json()\n",
+    "completion_text = ret[\"text\"]\n",
+    "speed = ret[\"meta_info\"][\"completion_tokens\"] / latency\n",
+    "\n",
+    "print_highlight(completion_text)\n",
+    "print_highlight(f\"speed: {speed:.2f} token/s\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "terminate_process(server_process)"
+   ]
+  }
+ ],
+ "metadata": {
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}

docs/index.rst

@@ -29,6 +29,7 @@ The core features include:
    backend/native_api.ipynb
    backend/offline_engine_api.ipynb
    backend/structured_outputs.ipynb
+   backend/speculative_decoding.ipynb
    backend/function_calling.ipynb
    backend/server_arguments.md