@@ -10,3 +10,22 @@ A: Assuming that you're referring to using OpenAI compatible server to serve mul
Q: Which model to use for offline inference embedding?
A: If you want to use an embedding model, try: https://huggingface.co/intfloat/e5-mistral-7b-instruct. Instead models, such as Llama-3-8b, Mistral-7B-Instruct-v0.3, are generation models rather than an embedding model
----------------------------------------
Q: Can the output of a prompt vary across runs in vLLM?
A: Yes, it can. vLLM does not guarantee stable log probabilities (logprobs) for the output tokens. Variations in logprobs may occur due to
numerical instability in Torch operations or non-deterministic behavior in batched Torch operations when batching changes. For more details,
see the `Numerical Accuracy section <https://pytorch.org/docs/stable/notes/numerical_accuracy.html#batched-computations-or-slice-computations>`_.
In vLLM, the same requests might be batched differently due to factors such as other concurrent requests,
changes in batch size, or batch expansion in speculative decoding. These batching variations, combined with numerical instability of Torch operations,
can lead to slightly different logit/logprob values at each step. Such differences can accumulate, potentially resulting in
different tokens being sampled. Once a different token is sampled, further divergence is likely.
**Mitigation Strategies**
- For improved stability and reduced variance, use `float32`. Note that this will require more memory.
- If using `bfloat16`, switching to `float16` can also help.
- Using request seeds can aid in achieving more stable generation for temperature > 0, but discrepancies due to precision differences may still occur.
vLLM supports only named function calling in the chat completion API by default. It does so using Outlines, so this is
enabled by default, and will work with any supported model. You are guaranteed a validly-parsable function call - not a
high-quality one.
To use a named function, you need to define the functions in the `tools` parameter of the chat completion request, and
specify the `name` of one of the tools in the `tool_choice` parameter of the chat completion request.
### Config file
The `serve` module can also accept arguments from a config file in
`yaml` format. The arguments in the yaml must be specified using the
long form of the argument outlined [here](https://docs.vllm.ai/en/latest/serving/openai_compatible_server.html#command-line-arguments-for-the-server):
For example:
```yaml
# config.yaml
host:"127.0.0.1"
port:6379
uvicorn-log-level:"info"
```
```bash
$ vllm serve SOME_MODEL --config config.yaml
```
---
**NOTE**
In case an argument is supplied simultaneously using command line and the config file, the value from the commandline will take precedence.
The order of priorities is `command line > config file values > defaults`.
---
## Tool calling in the chat completion API
vLLM supports only named function calling in the chat completion API. The `tool_choice` options `auto` and `required` are **not yet supported** but on the roadmap.
To use a named function you need to define the function in the `tools` parameter and call it in the `tool_choice` parameter.
It is the callers responsibility to prompt the model with the tool information, vLLM will not automatically manipulate the prompt. **This may change in the future.**
It is the callers responsibility to prompt the model with the tool information, vLLM will not automatically manipulate the prompt.
vLLM will use guided decoding to ensure the response matches the tool parameter object defined by the JSON schema in the `tools` parameter.
Please refer to the OpenAI API reference documentation for more information.
### Automatic Function Calling
To enable this feature, you should set the following flags:
*`--enable-auto-tool-choice` -- **mandatory** Auto tool choice. tells vLLM that you want to enable the model to generate its own tool calls when it
deems appropriate.
*`--tool-call-parser` -- select the tool parser to use - currently either `hermes` or `mistral` or `llama3_json` or `internlm`. Additional tool parsers
will continue to be added in the future, and also can register your own tool parsers in the `--tool-parser-plugin`.
*`--tool-parser-plugin` -- **optional** tool parser plugin used to register user defined tool parsers into vllm, the registered tool parser name can be specified in `--tool-call-parser`.
*`--chat-template` -- **optional** for auto tool choice. the path to the chat template which handles `tool`-role messages and `assistant`-role messages
that contain previously generated tool calls. Hermes, Mistral and Llama models have tool-compatible chat templates in their
`tokenizer_config.json` files, but you can specify a custom template. This argument can be set to `tool_use` if your model has a tool use-specific chat
template configured in the `tokenizer_config.json`. In this case, it will be used per the `transformers` specification. More on this [here](https://huggingface.co/docs/transformers/en/chat_templating#why-do-some-models-have-multiple-templates)
from HuggingFace; and you can find an example of this in a `tokenizer_config.json`[here](https://huggingface.co/NousResearch/Hermes-2-Pro-Llama-3-8B/blob/main/tokenizer_config.json)
If your favorite tool-calling model is not supported, please feel free to contribute a parser & tool use chat template!
#### Hermes Models
All Nous Research Hermes-series models newer than Hermes 2 Pro should be supported.
*`NousResearch/Hermes-2-Pro-*`
*`NousResearch/Hermes-2-Theta-*`
*`NousResearch/Hermes-3-*`
_Note that the Hermes 2 **Theta** models are known to have degraded tool call quality & capabilities due to the merge
step in their creation_.
Flags: `--tool-call-parser hermes`
#### Mistral Models
Supported models:
*`mistralai/Mistral-7B-Instruct-v0.3` (confirmed)
* Additional mistral function-calling models are compatible as well.
Known issues:
1. Mistral 7B struggles to generate parallel tool calls correctly.
2. Mistral's `tokenizer_config.json` chat template requires tool call IDs that are exactly 9 digits, which is
much shorter than what vLLM generates. Since an exception is thrown when this condition
is not met, the following additional chat templates are provided:
*`examples/tool_chat_template_mistral.jinja` - this is the "official" Mistral chat template, but tweaked so that
it works with vLLM's tool call IDs (provided `tool_call_id` fields are truncated to the last 9 digits)
*`examples/tool_chat_template_mistral_parallel.jinja` - this is a "better" version that adds a tool-use system prompt
when tools are provided, that results in much better reliability when working with parallel tool calling.
The tool calling that is supported is the [JSON based tool calling](https://llama.meta.com/docs/model-cards-and-prompt-formats/llama3_1/#json-based-tool-calling).
Other tool calling formats like the built in python tool calling or custom tool calling are not supported.
Known issues:
1. Parallel tool calls are not supported.
2. The model can generate parameters with a wrong format, such as generating
an array serialized as string instead of an array.
The `tool_chat_template_llama3_json.jinja` file contains the "official" Llama chat template, but tweaked so that
A tool parser plugin is a Python file containing one or more ToolParser implementations. You can write a ToolParser similar to the `Hermes2ProToolParser` in vllm/entrypoints/openai/tool_parsers/hermes_tool_parser.py.
"[user] Write a SQL query to answer the question based on the table schema.\n\n context: CREATE TABLE table_name_11 (nationality VARCHAR, elector VARCHAR)\n\n question: When Anchero Pantaleone was the elector what is under nationality? [/user] [assistant]",# noqa: E501
SamplingParams(n=3,
best_of=3,
use_beam_search=True,
temperature=0,
max_tokens=128,
stop_token_ids=[32003]),
LoRARequest("sql-lora",1,lora_path)),
(
"[user] Write a SQL query to answer the question based on the table schema.\n\n context: CREATE TABLE table_name_74 (icao VARCHAR, airport VARCHAR)\n\n question: Name the ICAO for lilongwe international airport [/user] [assistant]",# noqa: E501
SamplingParams(temperature=0.0,
...
...
@@ -60,15 +51,6 @@ def create_test_prompts(
max_tokens=128,
stop_token_ids=[32003]),
LoRARequest("sql-lora2",2,lora_path)),
(
"[user] Write a SQL query to answer the question based on the table schema.\n\n context: CREATE TABLE table_name_11 (nationality VARCHAR, elector VARCHAR)\n\n question: When Anchero Pantaleone was the elector what is under nationality? [/user] [assistant]",# noqa: E501
Each line represents a separate request. See the [OpenAI package reference](https://platform.openai.com/docs/api-reference/batch/requestInput) for more details.
**NOTE:** We currently only support to `/v1/chat/completions`endpoint (embeddings and completions coming soon).
**NOTE:** We currently only support `/v1/chat/completions`and`/v1/embeddings` endpoints (completions coming soon).
## Pre-requisites
...
...
@@ -21,7 +21,7 @@
- Get access to the gated model by [visiting the model card](https://huggingface.co/meta-llama/Meta-Llama-3-8B-Instruct) and agreeing to the terms and conditions.
You should now have your results at `results.jsonl`. You can check your results by running `cat results.jsonl`
```
$ cat ../results.jsonl
$ cat results.jsonl
{"id":"vllm-383d1c59835645aeb2e07d004d62a826","custom_id":"request-1","response":{"id":"cmpl-61c020e54b964d5a98fa7527bfcdd378","object":"chat.completion","created":1715633336,"model":"meta-llama/Meta-Llama-3-8B-Instruct","choices":[{"index":0,"message":{"role":"assistant","content":"Hello! It's great to meet you! I'm here to help with any questions or tasks you may have. What's on your mind today?"},"logprobs":null,"finish_reason":"stop","stop_reason":null}],"usage":{"prompt_tokens":25,"total_tokens":56,"completion_tokens":31}},"error":null}
Presigned put urls can only be generated via the SDK. You can run the following python script to generate your presigned urls. Be sure to replace the `MY_BUCKET`, `MY_INPUT_FILE.jsonl`, and `MY_OUTPUT_FILE.jsonl` placeholders with your bucket and file names.
Presigned urls can only be generated via the SDK. You can run the following python script to generate your presigned urls. Be sure to replace the `MY_BUCKET`, `MY_INPUT_FILE.jsonl`, and `MY_OUTPUT_FILE.jsonl` placeholders with your bucket and file names.
(The script is adapted from https://github.com/awsdocs/aws-doc-sdk-examples/blob/main/python/example_code/s3/s3_basics/presigned_url.py)
...
...
@@ -170,3 +170,36 @@ Your results are now on S3. You can view them in your terminal by running
```
aws s3 cp s3://MY_BUCKET/MY_OUTPUT_FILE.jsonl -
```
## Example 4: Using embeddings endpoint
### Additional prerequisites
* Ensure you are using `vllm >= 0.5.5`.
### Step 1: Create your batch file
Add embedding requests to your batch file. The following is an example:
```
{"custom_id": "request-1", "method": "POST", "url": "/v1/embeddings", "body": {"model": "intfloat/e5-mistral-7b-instruct", "input": "You are a helpful assistant."}}
{"custom_id": "request-2", "method": "POST", "url": "/v1/embeddings", "body": {"model": "intfloat/e5-mistral-7b-instruct", "input": "You are an unhelpful assistant."}}
```
You can even mix chat completion and embedding requests in the batch file, as long as the model you are using supports both chat completion and embeddings (note that all requests must use the same model).
### Step 2: Run the batch
You can run the batch using the same command as in earlier examples.
### Step 3: Check your results
You can check your results by running `cat results.jsonl`