[doc] Add more details for Ray-based DP

[ruisearch42]

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.

Purpose

• Add more details for Ray-based DP
• Use similar parameters (e.g., -data-parallel-size 4 rather than -data-parallel-size 16) so that readers can more easily relate

Test Plan

N/A

Test Result

N/A

(Optional) Documentation Update

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[gemini-code-assist]

Summary of Changes

Hello @ruisearch42, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the documentation for Ray-based data parallel deployment, making it clearer and more informative for users. It provides updated examples and explains the specific benefits and operational differences when leveraging Ray as the backend for distributed serving.

Highlights

• Improved Example: Updated the example command for Ray-based DP to use more relatable and practical parameters, specifically changing --data-parallel-size from 16 to 4 and adding --data-parallel-size-local 2 and --data-parallel-address.
• Key Differences Explained: Added a new section detailing the notable differences and advantages when using Ray for data parallel deployment, such as the convenience of a single launch command, automatic resource allocation for remote ranks, and the elimination of the need to specify --data-parallel-rpc-port.

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[gemini-code-assist]

Code Review

This pull request adds more details for Ray-based DP, using similar parameters for easier understanding. The review suggests removing an unnecessary argument from the example command to avoid potential user confusion.

[yewentao256]

Looks good to me, thanks for the work!

[hmellor]

LGTM