vllm/docs/source/contributing/profiling/profiling_index.rst
Russell Bryant 3a7f15a398
[Doc] Move CONTRIBUTING to docs site (#9924)
Signed-off-by: Russell Bryant <rbryant@redhat.com>
2024-11-08 05:15:12 +00:00

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==============
Profiling vLLM
==============
We support tracing vLLM workers using the ``torch.profiler`` module. You can enable tracing by setting the ``VLLM_TORCH_PROFILER_DIR`` environment variable to the directory where you want to save the traces: ``VLLM_TORCH_PROFILER_DIR=/mnt/traces/``
The OpenAI server also needs to be started with the ``VLLM_TORCH_PROFILER_DIR`` environment variable set.
When using ``benchmarks/benchmark_serving.py``, you can enable profiling by passing the ``--profile`` flag.
.. warning::
Only enable profiling in a development environment.
Traces can be visualized using https://ui.perfetto.dev/.
.. tip::
Only send a few requests through vLLM when profiling, as the traces can get quite large. Also, no need to untar the traces, they can be viewed directly.
.. tip::
To stop the profiler - it flushes out all the profile trace files to the directory. This takes time, for example for about 100 requests worth of data for a llama 70b, it takes about 10 minutes to flush out on a H100.
Set the env variable VLLM_RPC_TIMEOUT to a big number before you start the server. Say something like 30 minutes.
``export VLLM_RPC_TIMEOUT=1800000``
Example commands and usage:
===========================
Offline Inference:
------------------
Refer to `examples/offline_inference_with_profiler.py <https://github.com/vllm-project/vllm/blob/main/examples/offline_inference_with_profiler.py>`_ for an example.
OpenAI Server:
--------------
.. code-block:: bash
VLLM_TORCH_PROFILER_DIR=./vllm_profile python -m vllm.entrypoints.openai.api_server --model meta-llama/Meta-Llama-3-70B
benchmark_serving.py:
.. code-block:: bash
python benchmarks/benchmark_serving.py --backend vllm --model meta-llama/Meta-Llama-3-70B --dataset-name sharegpt --dataset-path sharegpt.json --profile --num-prompts 2