fix ibm benchmark on frontier + amd by anandrdbz · Pull Request #1159 · MFlowCode/MFC

anandrdbz · 2026-02-18T02:59:06Z

User description

Description

Simple bug fix that was introduced in a recent PR; AMD compilers don't like update device when the array bounds are 1:0.

Fixes #(issue)

Type of change

Testing

How did you test your changes?

Checklist

I added or updated tests for new behavior
I updated documentation if user-facing behavior changed

See the developer guide for full coding standards.

GPU changes (expand if you modified src/simulation/)

GPU results match CPU results
Tested on NVIDIA GPU or AMD GPU

CodeAnt-AI Description

Prevent GPU update when there are zero ghost points to avoid AMD failure

What Changed

The subroutine returns immediately when the ghost-point count is less than 1, so no GPU update or kernel launch is attempted for empty arrays
Removes the condition that caused AMD compilers or runtimes to reject an update with an array slice of bounds 1:0
All other behavior for non-empty ghost-point arrays is unchanged

Impact

✅ Runs IBM benchmark on Frontier without AMD compile/runtime error
✅ Fewer GPU launch failures when arrays are empty
✅ Stable execution when no ghost points are present

💡 Usage Guide

Checking Your Pull Request

Every time you make a pull request, our system automatically looks through it. We check for security issues, mistakes in how you're setting up your infrastructure, and common code problems. We do this to make sure your changes are solid and won't cause any trouble later.

Talking to CodeAnt AI

Got a question or need a hand with something in your pull request? You can easily get in touch with CodeAnt AI right here. Just type the following in a comment on your pull request, and replace "Your question here" with whatever you want to ask:

@codeant-ai ask: Your question here

This lets you have a chat with CodeAnt AI about your pull request, making it easier to understand and improve your code.

Example

@codeant-ai ask: Can you suggest a safer alternative to storing this secret?

Preserve Org Learnings with CodeAnt

You can record team preferences so CodeAnt AI applies them in future reviews. Reply directly to the specific CodeAnt AI suggestion (in the same thread) and replace "Your feedback here" with your input:

@codeant-ai: Your feedback here

This helps CodeAnt AI learn and adapt to your team's coding style and standards.

Example

@codeant-ai: Do not flag unused imports.

Retrigger review

Ask CodeAnt AI to review the PR again, by typing:

@codeant-ai: review

Check Your Repository Health

To analyze the health of your code repository, visit our dashboard at https://app.codeant.ai. This tool helps you identify potential issues and areas for improvement in your codebase, ensuring your repository maintains high standards of code health.

Summary by CodeRabbit

Bug Fixes
- Improved performance by preventing unnecessary processing when no items require computation.

codeant-ai · 2026-02-18T02:59:09Z

CodeAnt AI is reviewing your PR.

Thanks for using CodeAnt! 🎉

We're free for open-source projects. if you're enjoying it, help us grow by sharing.

Share on X ·
Reddit ·
LinkedIn

coderabbitai · 2026-02-18T02:59:27Z

📝 Walkthrough

Walkthrough

An early exit condition is added to the s_apply_levelset function that immediately returns when the number of ghost points is less than 1, skipping GPU updates and per-ghost-point processing.

Changes

Cohort / File(s)	Summary
Early Exit Optimization `src/simulation/m_compute_levelset.fpp`	Added guard clause in `s_apply_levelset` to skip processing when `num_gps < 1`, preventing unnecessary GPU updates and ghost-point iterations.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~5 minutes

Suggested labels

Review effort 2/5, size:XS

Poem

🐰 An early exit, swift and clean,
When zero ghosts dance on the scene,
No GPU load, no loops to spin,
Just skip and return—optimization wins! ✨

🚥 Pre-merge checks | ✅ 1 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The pull request description includes most required sections but lacks critical testing details and GPU verification confirmations despite modifying GPU code.	Complete the Testing section with specific test procedures, and confirm GPU parity checks and AMD GPU testing in the GPU changes section by checking the appropriate boxes.
Title check	❓ Inconclusive	The title 'fix ibm benchmark on frontier + amd' is somewhat vague and lacks specificity about the actual bug being fixed.	Clarify the title to mention the core issue (e.g., 'Prevent GPU update when ghost-point array bounds are empty') for better clarity about the specific bug being addressed.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

🧪 Generate unit tests (beta)

Create PR with unit tests
Post copyable unit tests in a comment

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

codeant-ai · 2026-02-18T03:01:18Z

Nitpicks 🔍

🔒 No security issues identified
⚡ Recommended areas for review GPU update guarding The root cause is a GPU update with an array slice `gps(1:num_gps)` when num_gps==0. A safer pattern is to guard individual GPU directives/launches with a conditional (so only GPU calls are skipped) rather than returning from the entire subroutine. This keeps CPU-side behaviors intact if the routine evolves. Early-return semantics The added early return (when there are no ghost points) prevents any further execution of the subroutine. This is likely intentional to avoid launching GPU updates with an empty slice, but it also skips every subsequent statement (including non-GPU logic that might be added later). Confirm that skipping all remaining code for num_gps <= 0 is correct for all current and future callers.

codeant-ai · 2026-02-18T03:01:21Z

CodeAnt AI finished reviewing your PR.

cubic-dev-ai

No issues found across 1 file

Confidence score: 5/5

Automated review surfaced no issues in the provided summaries.
No files require special attention.

codecov · 2026-02-18T05:43:17Z

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 44.06%. Comparing base (c5493c1) to head (8095bb3).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
src/simulation/m_compute_levelset.fpp	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1159      +/-   ##
==========================================
- Coverage   44.07%   44.06%   -0.01%     
==========================================
  Files          70       70              
  Lines       20431    20431              
  Branches     1974     1975       +1     
==========================================
- Hits         9004     9003       -1     
  Misses      10291    10291              
- Partials     1136     1137       +1

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

fix ibm benchmark on frontier + amd

8095bb3

codeant-ai bot added the size:XS This PR changes 0-9 lines, ignoring generated files label Feb 18, 2026

cubic-dev-ai bot reviewed Feb 18, 2026

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

fix ibm benchmark on frontier + amd#1159

fix ibm benchmark on frontier + amd#1159
anandrdbz wants to merge 1 commit intoMFlowCode:masterfrom
anandrdbz:master

anandrdbz commented Feb 18, 2026 •

edited by coderabbitai bot

Loading

Uh oh!

codeant-ai bot commented Feb 18, 2026

Uh oh!

coderabbitai bot commented Feb 18, 2026 •

edited

Loading

Walkthrough

Changes

Estimated code review effort

Suggested labels

Poem

❌ Failed checks (1 warning, 1 inconclusive)

Uh oh!

codeant-ai bot commented Feb 18, 2026

Uh oh!

codeant-ai bot commented Feb 18, 2026

Uh oh!

cubic-dev-ai bot left a comment

Uh oh!

codecov bot commented Feb 18, 2026

Uh oh!

Reviewers

Assignees

Labels

Milestone

Development

Uh oh!

1 participant

Conversation

anandrdbz commented Feb 18, 2026 • edited by coderabbitai bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

User description

Description

Type of change

Testing

Checklist

CodeAnt-AI Description

What Changed

Impact

Checking Your Pull Request

Talking to CodeAnt AI

Example

Preserve Org Learnings with CodeAnt

Example

Retrigger review

Check Your Repository Health

Summary by CodeRabbit

Uh oh!

codeant-ai bot commented Feb 18, 2026

Thanks for using CodeAnt! 🎉

Uh oh!

coderabbitai bot commented Feb 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Walkthrough

Changes

Estimated code review effort

Suggested labels

Poem

❌ Failed checks (1 warning, 1 inconclusive)

Uh oh!

codeant-ai bot commented Feb 18, 2026

Nitpicks 🔍

Uh oh!

codeant-ai bot commented Feb 18, 2026

Uh oh!

cubic-dev-ai bot left a comment

Choose a reason for hiding this comment

Uh oh!

codecov bot commented Feb 18, 2026

Codecov Report

Uh oh!

Reviewers

Assignees

Labels

Milestone

Development

Uh oh!

1 participant

anandrdbz commented Feb 18, 2026 •

edited by coderabbitai bot

Loading

coderabbitai bot commented Feb 18, 2026 •

edited

Loading