lora.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# LoRA Serving"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "SGLang enables the use of [LoRA adapters](https://arxiv.org/abs/2106.09685) with a base model. By incorporating techniques from [S-LoRA](https://arxiv.org/pdf/2311.03285) and [Punica](https://arxiv.org/pdf/2310.18547), SGLang can efficiently support multiple LoRA adapters for different sequences within a single batch of inputs."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Arguments for LoRA Serving"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The following server arguments are relevant for multi-LoRA serving:\n",
    "\n",
    "* `lora_paths`: A mapping from each adaptor's name to its path, in the form of `{name}={path} {name}={path}`.\n",
    "\n",
    "* `max_loras_per_batch`: Maximum number of adaptors used by each batch. This argument can affect the amount of GPU memory reserved for multi-LoRA serving, so it should be set to a smaller value when memory is scarce. Defaults to be 8.\n",
    "\n",
    "* `lora_backend`: The backend of running GEMM kernels for Lora modules. It can be one of `triton` or `flashinfer`, and set to `triton` by default. For better performance and stability, we recommend using the Triton LoRA backend. In the future, faster backend built upon Cutlass or Cuda kernels will be added.\n",
    "\n",
    "* `tp_size`: LoRA serving along with Tensor Parallelism is supported by SGLang. `tp_size` controls the number of GPUs for tensor parallelism. More details on the tensor sharding strategy can be found in [S-Lora](https://arxiv.org/pdf/2311.03285) paper.\n",
    "\n",
    "From client side, the user needs to provide a list of strings as input batch, and a list of adaptor names that each input sequence corresponds to."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Usage\n",
    "\n",
    "### Serving Single Adaptor"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from sglang.test.test_utils import is_in_ci\n",
    "\n",
    "if is_in_ci():\n",
    "    from patch import launch_server_cmd\n",
    "else:\n",
    "    from sglang.utils import launch_server_cmd\n",
    "\n",
    "from sglang.utils import wait_for_server, terminate_process\n",
    "\n",
    "import json\n",
    "import requests"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "server_process, port = launch_server_cmd(\n",
    "    \"\"\"\n",
    "python3 -m sglang.launch_server --model-path meta-llama/Meta-Llama-3.1-8B-Instruct \\\n",
    "    --lora-paths lora0=algoprog/fact-generation-llama-3.1-8b-instruct-lora \\\n",
    "    --max-loras-per-batch 1 --lora-backend triton \\\n",
    "    --disable-cuda-graph --disable-radix-cache\n",
    "\"\"\"\n",
    ")\n",
    "\n",
    "wait_for_server(f\"http://localhost:{port}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "url = f\"http://127.0.0.1:{port}\"\n",
    "json_data = {\n",
    "    \"text\": [\n",
    "        \"List 3 countries and their capitals.\",\n",
    "        \"AI is a field of computer science focused on\",\n",
    "    ],\n",
    "    \"sampling_params\": {\"max_new_tokens\": 32, \"temperature\": 0},\n",
    "    # The first input uses lora0, and the second input uses the base model\n",
    "    \"lora_path\": [\"lora0\", None],\n",
    "}\n",
    "response = requests.post(\n",
    "    url + \"/generate\",\n",
    "    json=json_data,\n",
    ")\n",
    "print(f\"Output 0: {response.json()[0]['text']}\")\n",
    "print(f\"Output 1: {response.json()[1]['text']}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "terminate_process(server_process)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Serving Multiple Adaptors"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "server_process, port = launch_server_cmd(\n",
    "    \"\"\"\n",
    "python3 -m sglang.launch_server --model-path meta-llama/Meta-Llama-3.1-8B-Instruct \\\n",
    "    --lora-paths lora0=algoprog/fact-generation-llama-3.1-8b-instruct-lora \\\n",
    "    lora1=Nutanix/Meta-Llama-3.1-8B-Instruct_lora_4_alpha_16 \\\n",
    "    --max-loras-per-batch 2 --lora-backend triton \\\n",
    "    --disable-cuda-graph --disable-radix-cache\n",
    "\"\"\"\n",
    ")\n",
    "\n",
    "wait_for_server(f\"http://localhost:{port}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "url = f\"http://127.0.0.1:{port}\"\n",
    "json_data = {\n",
    "    \"text\": [\n",
    "        \"List 3 countries and their capitals.\",\n",
    "        \"AI is a field of computer science focused on\",\n",
    "    ],\n",
    "    \"sampling_params\": {\"max_new_tokens\": 32, \"temperature\": 0},\n",
    "    # The first input uses lora0, and the second input uses lora1\n",
    "    \"lora_path\": [\"lora0\", \"lora1\"],\n",
    "}\n",
    "response = requests.post(\n",
    "    url + \"/generate\",\n",
    "    json=json_data,\n",
    ")\n",
    "print(f\"Output 0: {response.json()[0]['text']}\")\n",
    "print(f\"Output 1: {response.json()[1]['text']}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "terminate_process(server_process)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Future Works\n",
    "\n",
    "The development roadmap for LoRA-related features can be found in this [issue](https://github.com/sgl-project/sglang/issues/2929). Currently Cuda graph and radix attention are not incompatible with LoRA and must be manually disabled. Other features, including Unified Paging, Cutlass backend, and dynamic loading/unloadingm, are still under development."
   ]
  }
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