[Platform] Deprecate seed_everything

[wangxiyuan]

Purpose

seed_everything platform interface is totally useless, no platform redefine it It's always the same with

random.seed(seed)
np.random.seed(seed)
torch.manual_seed(seed)

Let's deprecate this interface to make the platform interface more clean.

Test Plan

Test Result

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.
• (Optional) Release notes update. If your change is user facing, please update the release notes draft in the Google Doc.

[mergify]

Documentation preview: https://vllm--31659.org.readthedocs.build/en/31659/

[gemini-code-assist]

Code Review

This pull request deprecates the seed_everything method from the platform interface and centralizes random seed setting into a new set_random_seed utility function in vllm.utils.torch_utils. This is a good cleanup that simplifies the platform interface. The changes involve updating numerous test files and internal utilities to use the new function.

I've identified a critical issue where the refactoring of set_random_seed is incomplete, which will break the build. I've also found several instances of redundant seed setting in the test files after the changes. Please see my comments for details on how to address these issues.

I am having trouble creating individual review comments. Click here to see my feedback.

vllm/model_executor/utils.py (13-16)

Moving set_random_seed to vllm.utils.torch_utils is a good refactoring. However, this change is incomplete as it doesn't update the call sites of this function. This will cause import errors and break the build.

The following files need to be updated to import set_random_seed from vllm.utils.torch_utils instead of vllm.model_executor.utils:

• vllm/engine/llm_engine.py
• vllm/worker/worker_base.py

Please update these files to complete the refactoring.

tests/kernels/attention/test_lightning_attn.py (125-126)

The call to set_random_seed(42) on line 127 already sets the seed for torch on all devices. These calls to torch.manual_seed and torch.cuda.manual_seed_all are redundant and can be removed.

tests/kernels/attention/test_lightning_attn.py (168-169)

The call to set_random_seed(42) on line 170 already sets the seed for torch on all devices. These calls to torch.manual_seed and torch.cuda.manual_seed_all are redundant and can be removed.

tests/kernels/attention/test_lightning_attn.py (232-233)

The call to set_random_seed(42) on line 234 already sets the seed for torch on all devices. These calls to torch.manual_seed and torch.cuda.manual_seed_all are redundant and can be removed.

tests/kernels/quantization/test_mxfp4_qutlass.py (210-211)

The call to set_random_seed(0) on line 209 already sets the seed for numpy and torch. These subsequent calls are redundant and can be removed.

tests/kernels/quantization/test_nvfp4_qutlass.py (198-199)

The call to set_random_seed(0) on line 197 already sets the seed for numpy and torch. These subsequent calls are redundant and can be removed.

[DarkLight1337]

Doesn't seed_everything include setting random.seed and np.random.seed as well? How can we replace it with only torch.manual_seed?

[DarkLight1337]

Edit: Contrary to the PR description, set_random_seed handles the other modules as well so it is fine

[wangxiyuan]

@DarkLight1337 My fault. Updated the commit message.

[yewentao256]

LGTM, thanks for the work!