[Misc] Add run one batch script that supports profiling

[LucasWilkinson]

add a script that runs one batch and can optionally profile it; e.g.

python examples/offline_inference/run_one_batch.py --model deepseek-ai/DeepSeek-V2-Lite --tensor-parallel-size 1 --max-model-len 1024 --gpu-memory-utilization 0.9 --kv-cache-dtype fp8 --trust-remote-code --profile both --profile-dir ./profiles/main

[mergify]

Documentation preview: https://vllm--32968.org.readthedocs.build/en/32968/

[gemini-code-assist]

Code Review

This pull request introduces a new example script for running a single batch inference with optional profiling capabilities. The script is well-structured and serves its purpose as a clear example. I've identified one high-severity issue related to input validation for the profiling directory path, which could lead to a crash. My suggestion addresses this by adding a check to ensure the path is a valid directory.

[gemini-code-assist]

The script crashes if --profile-dir points to an existing file instead of a directory. This is because the underlying PyTorch profiler expects a directory path and will fail when trying to create it if a file with the same name exists. Adding a check to validate the path will make the script more robust and prevent unexpected crashes.

Suggested change

	if not profile_dir:
	raise ValueError("--profile-dir must be set when profiling is enabled.")
	if not profile_dir:
	raise ValueError("--profile-dir must be set when profiling is enabled.")
	import os
	if os.path.exists(profile_dir) and not os.path.isdir(profile_dir):
	raise ValueError(
	f"--profile-dir '{profile_dir}' exists and is not a directory.")

[mergify]

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