[cumal]

Summary

Allow split backend over multiple cuda gpus

Related Issue / Discussion

#2225

Additional Information

Checklist

• I have read and confirmed this PR follows the contribution guidelines.

Summary by CodeRabbit

• Bug Fixes
  • Improved graph partitioning so each valid node keeps its first assignment rather than being reassigned by later segments. This also avoids assigning nodes that are missing or invalid, helping produce more consistent partitioning results.

[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

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• Review profile: CHILL
• Plan: Advanced
• Run ID: 63aecaf4-7d6b-457b-a143-aa47dc7dce5b

Commits

Reviewing files that changed from the base of the PR and between 290148d and 5b4f4a3.

Files selected for processing: 1

• src/core/layer_split_partition.cpp

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Walkthrough

Graph partitioning now skips node assignments when an index is out of range or the node is null. It also preserves an existing assignment instead of replacing it with the current segment’s backend.

Changes: Graph partition assignment

Layer / File(s)	Summary
Guard node assignments src/core/layer_split_partition.cpp	A shared helper skips invalid indices and null nodes. It assigns the current segment’s backend only when the node has no existing assignment.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Possibly related issues

• leejet/stable-diffusion.cpp#2225 — The issue describes illegal CUDA memory access during multi-CUDA layer splitting, which is related to the partition assignment behavior changed here.

Suggested reviewers: leejet

Merge Risk: Low · up to 5b4f4

Some valid multi-CUDA graphs may incur extra cross-device transfers and work, but execution remains correct and the impact is limited to shared-producer graph shapes.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentat…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Title check		The title clearly identifies the main change: fixing layer splitting across CUDA. It is concise and related to the changeset.
Description check		The description includes the required Summary, Related Issue / Discussion, Additional Information, and Checklist sections. It explains the goal, links the related issue, and confirms the contribution …
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Description check

Explanation

The description includes the required Summary, Related Issue / Discussion, Additional Information, and Checklist sections. It explains the goal, links the related issue, and confirms the contribution guidelines checklist.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 1 functions across 1 files.

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

Finishing Touches

Generate unit tests (beta)

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[leejet]

Thank you for your contribution.