EVS Support (Video tokens pruning)

[BloodAxe]

Purpose

Enable use of Efficient Video Sampling (EVS) for redundant video tokens pruning:

llm = LLM(
    "nvidia/Cosmos-Reason1-7B",
    video_pruning_rate=0.75, # Prune 75% video tokens, effectively reducing TTFT 4x
    limit_mm_per_prompt={"image": 10, "video": 10},
)

EVS reduces TTFT and ITL by pruning less important vision tokens from the LLM:

Test Plan

• Added tests to verify inference with EVS on/off works as expected

Test Result

(Optional) Documentation Update

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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.

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @BloodAxe.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[gemini-code-assist]

Code Review

This pull request adds support for Efficient Video Sampling (EVS) by introducing a new interface for models to return custom embeddings and positions, which enables video token pruning. While the overall direction is good, there are several critical issues that need to be addressed. The new interface signature in interfaces.py is inconsistent with its usage in gpu_model_runner.py. More importantly, the logic for updating request states with the pruned positions appears to be incorrect, as it applies the same update to all requests in a batch. Additionally, there are several leftover debugging statements and commented-out code that should be cleaned up before merging.

[github-actions]

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @BloodAxe.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[DarkLight1337]

Sorry for the delay, let's get this merged