samples: skip unsupported test case, remove invalid cudaGraphDestroy

[dextero]

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Affected area

• Documentation or samples

Summary

• Skip deterministic SDPA backward in sample when running on Blackwell with tool old cuDNN. This is explicitly marked as unsupported in the code.
• Remove invalid cudaGraphDestroy(cudnn_cuda_graph_new) in cudagraphs sample. As per documentation of cudaGraphChildGraphNodeGetGraph it's owned by the parent main_cuda_graph and gets destroyed whenever the main one is.

Why

This makes the samples tests pass on older cuDNN.

Related issues

None

API and compatibility impact

None

Testing

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j $(nproc)
build/bin/samples
build/bin/legacy_samples

Summary by CodeRabbit

• Bug Fixes
  • Improved error handling during CUDA graph cleanup.
  • Added a compatibility skip for deterministic SDPA backward tests on Blackwell hardware with older cuDNN versions.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

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Review profile: CHILL

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📥 Commits

Reviewing files that changed from the base of the PR and between ae8705e and 659cd39.

📒 Files selected for processing (2)

• samples/cpp/misc/cudagraphs.cpp
• samples/cpp/sdpa/fp16_bwd.cpp

Included review availability: Your plan provides up to 12 included reviews per hour; 11 remain after this review.

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📝 Walkthrough

Walkthrough

The changes add CUDA status checks during graph cleanup, remove redundant cuDNN graph destruction, and skip unsupported deterministic SDPA backward execution on Blackwell with older cuDNN versions.

Changes

CUDA graph cleanup

Layer / File(s)	Summary
Checked graph destruction samples/cpp/misc/cudagraphs.cpp	cudaGraphExecDestroy and cudaGraphDestroy now use CUDA_CHECK. Explicit destruction of cudnn_cuda_graph_new was removed.

SDPA backward compatibility

Layer / File(s)	Summary
Deterministic SDPA compatibility skip samples/cpp/sdpa/fp16_bwd.cpp	The test skips deterministic SDPA backward execution on Blackwell when cuDNN is older than 9.18.0.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Merge Risk: ⚪ Minimal · up to 659cd

This localized sample change skips an unsupported test case and removes an invalid CUDA graph destruction call; no actionable merge-blocking risk remains after normal checks and review.

Suggested reviewers: anerudhan

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes both primary changes: skipping an unsupported test case and removing the invalid cudaGraphDestroy call.
Description check	✅ Passed	The description covers the affected area, summary, rationale, related issues, compatibility impact, and testing commands. The Milestone and Projects fields are not addressed, and test results are not …

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2 files.

Full details: Description check

Explanation

The description covers the affected area, summary, rationale, related issues, compatibility impact, and testing commands. The Milestone and Projects fields are not addressed, and test results are not reported, but the description is otherwise complete and relevant.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Anerudhan]

Thanks @dextero for the PR.
Merging